and yet another question

[Lloyd Smale]

Has anyone tried taking a pc bullet and conventionaly lube sizing it? I wonder if at high velocitys (over 2k) if the addition of a good lube wouldn't help you get even more velocity before problems start.

[noisewaterphd]

Has anyone tried taking a pc bullet and conventionaly lube sizing it? I wonder if at high velocitys (over 2k) if the addition of a good lube wouldn't help you get even more velocity before problems start.

I've tried it in a lot of loads. In some of my rifle loads it definitely tightened up groups.

The addition of lube definitely lowers pressure a bit from being more slippery, so it will drop your velocities some.

I haven't done enough thorough testing to know if it's the velocity drop that puts things back on target, but I'm thinking so. In which case, I should probably just save both powder and lube and drop the charge.

[mannparks]

Can't see the harm in lube over PC

[OS OK]

You know Lloyd…when you find the fastest round you can load safely, you need to start testing groups of that powder weight (if starting from max.) by subtracting .1 or .2 grains and test/group each in order to find the nearest 'node' in the barrel. To me, this as fast as I can shoot that cartridge combination. This is where accuracy will start to tighten up, tighten further by experimenting with the COAL and how close you can get to the lands without jamming it in and having a pressure spike at boolit start. I can't justify the tight clearance the Bench Shooters maintain with their jacketed rounds because there is some difference boolit to boolit on the thickness of the coating at the radius of the nose.

charlie

[rancher1913]

I do my 45-70 rounds like that but just because its easy to size and lube boolits that big and I figure the older guns like my trapdoor need all the help they can get.

[bangerjim]

There is not evidence of PC deterioration down inside the case when grease is applied and then the rounds stored for a time. But who knows!

I would not do it. No need.

I PC to get away from messing with brewing up witch's brews of grease, the mess of a lubramatic, and the sticky boolits in my guns.

PC is clean and easy and slick. And I get all the velocity I will EVER need with PC. (I do not hunt or kill living things with guns......just paper and water bottles). I do all my hunting on the menu at Outback!

banger

[noisewaterphd]

Larry G did a test, gained ~50 fps. Not worth the extra step for me. I did it to see if it gave any other benefits, found none.

Gained 50fps at the same charge weight? Or, was able to get an extra usable 50fps by upping the charge after lubing?

[Lloyd Smale]

never saw where a slick barrel was slower then a rough one so id have to doubt whether a slippery bullet is going to be slower then a not so slick one. Friction is going to slow something down. Pressure is whats created overcoming that friction.
I've tried it in a lot of loads. In some of my rifle loads it definitely tightened up groups.

The addition of lube definitely lowers pressure a bit from being more slippery, so it will drop your velocities some.

I haven't done enough thorough testing to know if it's the velocity drop that puts things back on target, but I'm thinking so. In which case, I should probably just save both powder and lube and drop the charge.

[noisewaterphd]

never saw where a slick barrel was slower then a rough one so id have to doubt whether a slippery bullet is going to be slower then a not so slick one. Friction is going to slow something down. Pressure is whats created overcoming that friction.

The problem with that statement is that it flies in the face of physics.

If you make a bullet more slippery, it will go slower at the same charge weight because less friction creates less pressure.

Physics tells us this.

Quickload will tell you this.

I have years, and years of log books that tell the same story.

[noisewaterphd]

How about an excerpt from an article on bullet coatings at Accurate Shooter:

Well, there is no free lunch. By reducing friction, bullet coating has the effect of reducing pressures in your barrel. This means that you'll get less velocity with coated bullets than naked bullets, given the same powder load. Anti-friction coatings are Speed Robbers. You can expect to lose 20-80 fps after coating your bullets, maybe more with large cartridges and bullets with long bearing surfaces. In order to get back to the velocity you had before coating your bullets, you'll need to adjust the powder load upwards--perhaps a half-grain or more. That's not a problem ... IF you have extra capacity in your case. If you've already maxed out your case capacity, you may need to change powders, or just accept the slower velocity as the "price" of coating your bullets.

JUST TO CLARIFY: The coating the article speaks of is not powder coating. The article is about anti-friction coatings like moly, tungsten disulfide, and hbn which are very slippery coatings.

PC is not an anti-friction coating. PC is less slick, creating more pressure, and more velocity than traditional lube. Not much, but some.

[Lloyd Smale]

then with your thinking the more fouled a bore becomes the fast its going to shoot? Or an corroded and pitted barrel will shoot faster then a match barrel?

[Spector]

I'll just interject this. I have during earlier PC efforts left PC residue n my barrel and it took some time to remove it. I never really understood why. A couple of days ago I rolled a PCed 300 grain .452'' Lee RF boolit under a blade held in the big lube groove to part off the upper part of the boolit. I weighed it and seated it in an old case just to see how far in I would have to seat it in order to chamber it in my XDs barrel. I heard a squeak as I started seating it. I noticed what felt sort of sticky on the clear powder coating and finally determined it was the coating itself squeaking as it created friction as I continued to seat it a little at a time.

Now, I am no scientist, but I am assuming this was an early batch I baked at about 375 and probably not over 10 minutes for my Ruger 45 Colt Bisley. And I am figuring I'll go back and re-bake these revolver boolits at 325 degrees for 15 minutes. If I am right the PS will harden off and the friction it creates will be much less as it is with other batches I have baked since then.

Properly cured PC is really slick. So perhaps PC can have a range of friction depending on how it was cured in an oven.

Just throwing it out there for consideration by those smarter than me to figure out if what I am suggesting is even possible. The squeaking upon seating and the increased press handle pressure needed to seat it was definitely not my imagination. I believe this batch of boolits would generate more pressure upon firing than other more properly cured batches I've baked since this batch. And I can imagine that traditional lube over PC could actually reduce that pressure.

If the PC is properly cured to meet our requirements I doubt traditional lube would be of significant benefit applied over the top of the PC.

Mike

[noisewaterphd]

then with your thinking the more fouled a bore becomes the fast its going to shoot? Or an corroded and pitted barrel will shoot faster then a match barrel?

Just to be clear Lloyd, this is not my thinking. No matter what you think, you are not arguing with me. I'm just trying to help you understand.

[noisewaterphd]

I'll just interject this. I have during earlier PC efforts left PC residue n my barrel and it took some time to remove it. I never really understood why. A couple of days ago I rolled a PCed 300 grain .452'' Lee RF boolit under a blade held in the big lube groove to part off the upper part of the boolit. I weighed it and seated it in an old case just to see how far in I would have to seat it in order to chamber it in my XDs barrel. I heard a squeak as I started seating it. I noticed what felt sort of sticky on the clear powder coating and finally determined it was the coating itself squeaking as it created friction as I continued to seat it a little at a time.

Now, I am no scientist, but I am assuming this was an early batch I baked at about 375 and probably not over 10 minutes for my Ruger 45 Colt Bisley. And I am figuring I'll go back and re-bake these revolver boolits at 325 degrees for 15 minutes. If I am right the PS will harden off and the friction it creates will be much less as it is with other batches I have baked since then.

Properly cured PC is really slick. So perhaps PC can have a range of friction depending on how it was cured in an oven.

Just throwing it out there for consideration by those smarter than me to figure out if what I am suggesting is even possible. The squeaking upon seating and the increased press handle pressure needed to seat it was definitely not my imagination. I believe this batch of boolits would generate more pressure upon firing than other more properly cured batches I've baked since this batch. And I can imagine that traditional lube over PC could actually reduce that pressure.

If the PC is properly cured to meet our requirements I doubt traditional lube would be of significant benefit applied over the top of the PC.

Mike

To be honest, I can't give you answers on the details of your post.

But, even the most slippery of PC still creates a bit more friction than traditional lube. But, this is not a bad thing, it's just a thing.

In fact, getting a bullet too slippery is what can actually be a bad thing, accuracy can go out the window. You actually need a certain amount of friction in order to maintain consistent pressures, and thus consistent POI.

[Lloyd Smale]

I'm not arguing with you personally about this either. I'm just trying to understand. Now I'm seeing that some consider pc not as friction free as conventional lubes. but some are posting a velocity loss over cast bullets?? This kind of favors my way of thinking that friction slows down a bullet doesn't it? Now I'm the first to admit I'm not RIFLE expert when it comes to cast bullets. Yes ive shot a lot of them but for the most part its been big bore slow stuff. I have though shots 100s of thousand cast bullets in the about a 100 handguns ive owned. Ive chronographed I don't know how many thousands of different loads. Ive never seen where jacketed bullets shot faster then cast. Ive actually seen it go both ways with certain powders and powder charges and bullets. For the most part I have to conclude that its a non issue. I have noticed though a slight drop in pressure with cast. Most of the rifles I shoot cast in haven't had a jacketed bullet though them but maybe once or twice if that. So I cant even say if I saw a drop in pressure with them. I was allways told a good load develops peak pressure at about the 1/3 point in a barrel. Be it a rifle or handgun. So my way of thinking (and no doubt I could be wrong) is that after that point friction is going to slow down a bullet and my way of thinking is that a given load may increase in pressure in a rougher barrel to enough to overcome that given friction but the friction wont actually cause it to produce enough more pressure to actually make it faster. that just doesn't make sense. Increase the friction in the drive train in your car by dragging your brakes driving 60mph and your motor will try produce more horsepower and torque to try to overcome it but it sure wont make you faster.


As to rifles I will say this because its the only real world experience I have and I don't hold much store in internet knowledge that I haven't seen myself. Ive had a few mag rifles one wby vanguard in 300 win mag with a 24 inch barrel and and a ruger 300 win mag with a 26 inch barrel. The wby had a nice smooth barrel and fouled very little. The ruger would foul in 10 shots to the point of doubling group sizes (now I'm talking jacketed bullets obviously). thing is load for load that 24 inch weatherby had about identical velocity to the ruger. Another example is the two 2506s I owned at the same time. One was a #1b with a 26 inch tube and not so smooth of a bore and the other was a custom interarms action with a douglas air gauged hand lapped (bought it from the factory hand lapped) 24 inch barrel. the interarms consistently gave slightly better velocity then the ruger did. Now this and the fact that about every handgun I ever hand lapped gave a few fps more with the same loads as before makes me doubt all this. Like is said though I'm no scientist and I'm not a rifle expert by any means and maybe my results were just "one of those things"

I guess to really know we need someone ON HERE that is trust worthy and has no preconceived opinions to do a test. First he would have to be scientific enough to actually measure which method actually does produce the least amount of friction. Then have access to two identical guns one with a smooth barrel and one with a rougher one. Then he would have to shoot identical loads in each. Same powder, primer, case, seating depth, and alloy. That you've done it in one gun wouldn't much answer this because I could take two different guns and get different answers. Really to be dead accurate youd probably need to guns with smooth bores and two with rough. things like headspace, how the chamber is cut, how the throat is cut all effect velocity in a rifle and in a handgun too as do other things. I will allways believe though that friction is the enemy of ANYTHING that you want to make faster. Be it a car, an airplane, a boat, or a gun. That is physics noisewater. problem here is even you guys that are the more experience at this cant even agree if this coating is a better and smoother lubricant then a conventional lube.

I look at it like this. Lead, tin and petroleum product are what bearing are made from and protected by. Ive yet to see a pc coated main or rod bearing in a car. i would have to guess the guys saying that lead and conventional lubes are the slipperier of the two and if so using your train of though you guys should be seeing an increase in velocity not a decrease. i know my heads about to burst:redneck: I also have to say i could give a rats @@@ if it gives 50 fps more or less velocity because in the real world it means nothing. I guess i just want the truth. Theres been so many wives tails in the history of casting. Things like bullets needing to be soft and bump up or that hard lead causes more leading then soft that have been disproved over and over and some still believe. I just don't want new ones created by some theorist that never even shot a bullet. sure not looking for a :takinWiz: match here though. Just some education.
Just to be clear Lloyd, this is not my thinking. No matter what you think, you are not arguing with me. I'm just trying to help you understand.

[Echd]

You can shoot identical jacketed bullets right next to moly coated ones and see velocity decrease for the slicker bullets. Less pressure is less speed.

Now, can you increase that load and end up somewhere else? That's another story with another unsatisfyingly inconsistent answer.

[Lloyd Smale]

where are you getting your facts?? Have you done extensive pressure testing or any for that matter? How about testing how much resistance to traveling down a bore coated bullets have vs cast vs jacketed. Or are you just passing on stuff you've read somewhere. Anyone can make up a theory on this and post it on the internet. Where are the actual tests?. theres guys on here that if they told me something they experienced it take it as wrote in stone. Guys with 30 or 40 years of experience at this stuff. But with only 500 posts I have to ask how long you've been even casting and loading.

Now that said I'm going to throw this one at you. You talk so much about increase in pressure meaning increase in velocitys. I'm here to tell you that its not allways the case. If it were wed never use slow powders. We wouldn't need to use them to get mag velocitys. Heres so data from the hodgdon manual on a 44 mag

with a 180 hp
23 grains of 2400 gave 33700 pressure 1440 for velocity
13 grains of unique gave 34900 pressure and 1250 for velocity

240 grain
18.7 2400 gave 34,800 and 1440 for velocity
7 bullseye gave 34900 and 1250

as you can see in the first case there was more velocity with less pressure using 2400
and the second one with the pressures the same 2400 whipped bullseye.

Now there is no argument that if I increase any of these charges the pressure goes up and so does the velocity but it also shows that your obsession with pressure as it relates to velocity isn't wrote in stone. you can easily spike pressures in a barrel without gaining velocity. I even seen when dealing with lilgun that when you push the envelope velocitys actually falls off.

[Echd]

First off, check your tone. You are attacking a person (rather than an idea) based on POST COUNT on a website. Think of how silly this is and how petty it makes you look. You are doing this because you don't understand a topic but don't like the answer multiple people have given you. Also I posted something you can do for extremely low cost with only a chronograph to verify what other people are telling you. Be an adult if you want to have an adult conversation.

Second, you are comparing pressures between different powders. This is absolutely apples and oranges for a lot of reasons, and if you don't know why then you should probably spend a bit more time at the reloading bench, and I actually do say that in a manner that isn't meant to be snarky- but you absolutely cannot compare different powders like that.

A small hint that describes part of why, in an extraordinarily oversimplified way:

Powder is burned to make a propellant gas which expels a bullet from a barrel.

You can have 7 units of a gas operating at 35000 psi or you can have 18.7 units of a gas operating at 35000 psi. Which data set has more "power" to push something with? Does being hit in the head with a wiffleball going 20 mph hurt as much or less than a bowling ball at the same speed?

Now go compare the same powder relative to pressures and you will see what everyone else is saying: less pressure is less speed within its own dataset. Take that 240 grain bullet with 18.7 grains of 2400 and molycoat it and watch the velocity drop from the uncoated version. Slightly, but it will drop.

The only one here making up some unusual theory is you, who has stated that slicker barrels- whatever that is supposed to mean- push bullets faster. "Tighter" barrels might tend to push bullets faster, but with accordingly higher pressures- and that is something you will see a lot of fighting about over on sites like sniper's hide- but "slicker" is largely unused, or else everyone would be titanium nitriding their barrels for maximum velocity or something like that.

ETA: I might not have 40 years of reloading- or be that old for that matter- but I spent enough time behind a desk and pushing a pencil to know how basic physics works. They even gave me a piece of paper that said I did!

[noisewaterphd]

Loyd, this is at least the second time you have inferred that post count == real world experience, or intelligence, which is one of the most ridiculous things you could be posting.


less pressure is less speed within its own dataset.

Loyd, pay attention to that post by Echd, you can't keep taking the argument out of context. Pressure and velocity do not rise in lockstep.

[Lloyd Smale]

what qualification do you and he have that I should take everything you say to the bank without a single doubt? All ive seen or heard are opinions. Where is the test data? It wasn't but two year ago that he was loading on a turrent press and bragging that on tumble lube as the best answer to lubing bullets.

[Echd]

I've had dillon presses for years, as well as turrets (Also, it's "turret", not "turrent"). I recently sold a redding T7 to a member here in an FTF transaction. Clearly that must have been a real piece of junk, right?

And tumble lube is a great option for lubing mass quantities of bullets. The only reason I don't use it anymore is because it gums up bullet feeders and I don't like cleaning my suppressors.

Again, physics aren't opinions. If you can't figure that out, then maybe crack a textbook. This isn't revolutionary data here.

Although, I've been powder coating for several years at the least, as well.

Maybe you're implying that much like physics, turret presses and tumble lubricants don't work?

Now, how about you cut the ad hominem.



Documentation from a ballistician at norma about pressure and velocity decrease resulting from bullet coatings:

http://www.6mmbr.com/normamoly.html

Some guy documenting velocity decreasing with pressure-reducing compounds:

http://www.all-science-fair-projects.com/print_project_1214_147

Guns Magazine

http://gunsmagazine.com/moly-yes-or-moly-no/

Let me cut the relevant snippet out just for you:


Once the bore has a thin coating of moly, when moly coated bullets are fired through it pressure is reduced, as is velocity.

More 6mmBR articles, with relevant quotation:

http://www.6mmbr.com/bulletcoating.html


Well, there is no free lunch. By reducing friction, bullet coating has the effect of reducing pressures in your barrel. This means that you'll get less velocity with coated bullets than naked bullets, given the same powder load. Anti-friction coatings are Speed Robbers. You can expect to lose 20-80 fps after coating your bullets, maybe more with large cartridges and bullets with long bearing surfaces. In order to get back to the velocity you had before coating your bullets, you'll need to adjust the powder load upwards--perhaps a half-grain or more. That's not a problem ... IF you have extra capacity in your case. If you've already maxed out your case capacity, you may need to change powders, or just accept the slower velocity as the "price" of coating your bullets.

From Accurate shooter:

http://bulletin.accurateshooter.com/tag/boron-nitride/


Coating bullets with a friction-reducing compound such as Molybdenum Disulfide (Moly) offers potential benefits, including reduced barrel heat, and being able to shoot longer strings of fire between bore cleanings. One of the effects of reduced friction can be the lessening of internal barrel pressures. This, in turn, means that coated bullets may run slower than naked bullets (with charges held equal). To restore velocities, shooters running coated bullets are inclined to “bump up” the load — but you need to be cautious.




Oh, and here's the biggest one of all, Bernoulli's Principle, which everyone has heard of (and erroneously attributed to airplanes)

Bernoulli's principle states that for an inviscid flow of a nonconducting fluid, an increase in the speed of the fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy.

(Yes, virginia, air is a fluid, at least in most contexts like this)

Within the same dataset, reducing pressure will reduce velocity.

[noisewaterphd]

what qualification do you and he have that I should take everything you say to the bank without a single doubt? All ive seen or heard are opinions. Where is the test data? It wasn't but two year ago that he was loading on a turrent press and bragging that on tumble lube as the best answer to lubing bullets.

Not opinions Lloyd, that's the point.

Also, what's wrong with a turret press, or tumble lubing for that matter? I fail to see either of those as the insult you intended them to be.

[Lloyd Smale]

nope post count doesn't guarantee anything. But I know the guys with high post counts have been here for a good long time. That to me at least means they been doing this for 10 years or more. Like I said to your buddy show me the proof. Not just lip service. Believe it or not I'm still here to learn. Many have come and gone here that thought they had the answers or could bs people into at least thinking they did. So teach me. Show me the facts.
Loyd, this is at least the second time you have inferred that post count == real world experience, or intelligence, which is one of the most ridiculous things you could be posting.



Loyd, pay attention to that post by Echd, you can't keep taking the argument out of context. Pressure and velocity do not rise in lockstep.

[Lloyd Smale]

Now I'm going to back out of this post. I will sit back and watch and see how much real proof will be shown. How much real world bullet shooting, bullet testing is done. I'm done with the :takinWiz: match. You guys my very well be experts on this but its going to take more then beating your chest. Show me actually pressure testing and testing of which is the smoothest bullets going down a bore. Show me examples of actual guns that were tested with rough barrels that showed velocity increases. Scientifically like you guys seem to like it. If you cant then id suggest just like me you back away like a gentleman.

[Echd]

Already stood up to it, pardner. But if you want to slink away with your tail between your legs given my most recent post, go right ahead. This wasn't a peeing contest until you started insulting people.

I don't know what other proof you want other than guiding principles of physics and the word of ballisticians at top companies.

[454PB]

Not my research, but worth watching, Lloyd:

https://www.youtube.com/watch?v=gu7UfKITMF8

[noisewaterphd]

Now I'm going to back out of this post. I will sit back and watch and see how much real proof will be shown. How much real world bullet shooting, bullet testing is done. I'm done with the :takinWiz: match. You guys my very well be experts on this but its going to take more then beating your chest. Show me actually pressure testing and testing of which is the smoothest bullets going down a bore. Show me examples of actual guns that were tested with rough barrels that showed velocity increases. Scientifically like you guys seem to like it. If you cant then id suggest just like me you back away like a gentleman.

You are the only one talking about guns with rough barrels, I'm guessing attempted misdirect.

I can totally get you pressure and velocity results for almost any caliber/bullet combination, you name it. Barrel lengths will be limited.

[Lloyd Smale]

I don't know what other proof you want other than guiding principles of physics and the word of ballisticians at top companies.

show me the money :bigsmyl2:



and the first personal attack was yours calling out my grammar. All I did was disagree with you and ask for REAL proof instead of opinion and I got just the answer I expected, generalizations, and more personal attacks and not one fact. Not any quote from any ballistician from any top company and certainly nothing from Isaac Newton or any other physicist. Again just you. This certainly isn't worth wasting another minute of my time on. I'm sure not going to get any real answers here. After two years you no doubt are one of the leading experts on coating bullets and how physics relates to ballistics. If I ever doubted it noisewater set me straight. [smilie=l:

[Echd]

Willful ignorance is an insidious thing, but you seem to lavish in it. Continue to reject simple things out of highschool textbooks in favor of insulting people on the internet if you will, I will enjoy being right. Being so right that a simple google search turns up page after page of evidence backing up the extremely simple idea that I am espousing...

And all over something so simple.

Also, I never insulted you once nor called out your grammar. You are the one flying off the handle over nothing at all... literally, a completely neutral statement was my first post in this thread. Mostly, I was just curious why posting




You can shoot identical jacketed bullets right next to moly coated ones and see velocity decrease for the slicker bullets. Less pressure is less speed.

Now, can you increase that load and end up somewhere else? That's another story with another unsatisfyingly inconsistent answer.



is met with


where are you getting your facts?? Have you done extensive pressure testing or any for that matter... Or are you just passing on stuff you've read somewhere. Anyone can make up a theory on this and post it on the internet. Where are the actual tests?. theres guys on here that if they told me something they experienced it take it as wrote in stone. Guys with 30 or 40 years of experience at this stuff. But with only 500 posts I have to ask how long you've been even casting and loading.


Generally speaking, baseless attacks on the source instead of the information presented are the textbook definition of an "ad adhominem" attack...

Which is odd when I, you know, showed you exactly how you can prove the thing you claim you want to know but deny at every turn... something which I have personally done, because molycoat was soooo cool in high power circles back then, and it proves how a slick bullet will have lower velocity with the same load. Playing with molycoating was old hat when I started reloading... surely you, with your infinite wealth of experience in practical matters would have tried that by now?

Guess it doesn't matter. I like to understand someone's thought processes... or lack thereof. Guess if you're really leaving the thread I won't know why you're so upset over it.

[noisewaterphd]

Lloyd, I've already told you that I'm happy to share my personal log books with you.

I also told you to name your cartridge and bullet (assuming I have access to the particular bullet), and I will give you the pressure, and velocity results. I can do this for most any round, some might require some new tooling, but it would have to be pretty obscure.

But, the exercise is pretty pointless. Again, these aren't opinions we are arguing about.

Still, I'm happy to do it.

[Lee S. Forsberg]

I just got here. What an argument!! I've read mostly about velocity not to much about accuracy. I've sized and lubed and applied gas checks over powder coating and it works just fine. I haven't measured velocities let alone the difference between PC and non PC bullets velocities. If I notice tighter groups with lubed PC bullets I might test the velocity just for fun so I know what it is. If lubed PC bullets don't group any better than PC only bullets I'll stop lubing them. Or for that matter if PC bullets don't show improved accuracy over lube only I'll stop powder coating. I'm looking for the correct velocity to produce the best accuracy.

[Lee S. Forsberg]

Has anyone tried taking a pc bullet and conventionaly lube sizing it? I wonder if at high velocitys (over 2k) if the addition of a good lube wouldn't help you get even more velocity before problems start. I just got here. What an argument!! I've read mostly about velocity not to much about accuracy. I've sized and lubed and applied gas checks over powder coating and it works just fine. I haven't measured velocities let alone the difference between PC and non PC bullets velocities. If I notice tighter groups with lubed PC bullets I might test the velocity just for fun so I know what it is. If lubed PC bullets don't group any better than PC only bullets I'll stop lubing them. Or for that matter if PC bullets don't show improved accuracy over lube only I'll stop powder coating. I'm looking for the correct velocity to produce the best accuracy.

[Lee S. Forsberg]

Sorry for the double post. Mods please delete one of them.

[Lloyd Smale]

lots of keyboard work just to say in the end I'm stupid and still not one iota of proof. Not one example of actual pressure testing a coated bullet to prove the pressure is lower and so is the velocity. Just more you "you can find it anywhere" Personally ive never seen a single high school text book that had anything to do with bullet casting or shooting of a gun in any way. But then ive lived up in the sticks all my life. I guess the guys I was friends with in NC didn't care much about book smart people either. They, like me went by what they saw what was put in front of them. they knew with a couple years experience and a couple books you could talk the talk but few have actually walked the walk. I guess in this case we will call it blissful ignorance because now theres nothing I want to learn from you and to think all it would have took is for you to do one of your simple google searchs and then because you like it so much, you could have been right. Ive been on this forum since 3 months after its inception. In that time ive only put two guys on my ignore list. Both of them eventually went away. They either decide that this wasn't there main hobby in life or realized they weren't wanted here. I don't know which. You will be my third so you can come back and lash out at me again and get the last work in and I wont even see it. :bigsmyl2: I know I wont miss any earth shattering knowledge over the next couple years and my guess is youll probably join the other two eventually anyway. See ya![smilie=s:
Willful ignorance is an insidious thing, but you seem to lavish in it. Continue to reject simple things out of highschool textbooks in favor of insulting people on the internet if you will, I will enjoy being right. Being so right that a simple google search turns up page after page of evidence backing up the extremely simple idea that I am espousing...

And all over something so simple.

Also, I never insulted you once nor called out your grammar. You are the one flying off the handle over nothing at all... literally, a completely neutral statement was my first post in this thread. Mostly, I was just curious why posting



is met with



Generally speaking, baseless attacks on the source instead of the information presented are the textbook definition of an "ad adhominem" attack...

Which is odd when I, you know, showed you exactly how you can prove the thing you claim you want to know but deny at every turn... something which I have personally done, because molycoat was soooo cool in high power circles back then, and it proves how a slick bullet will have lower velocity with the same load. Playing with molycoating was old hat when I started reloading... surely you, with your infinite wealth of experience in practical matters would have tried that by now?

Guess it doesn't matter. I like to understand someone's thought processes... or lack thereof. Guess if you're really leaving the thread I won't know why you're so upset over it.

[Echd]

I'd say it wasn't worth my time, but an attempt at battling ignorance always is. Oh well, you can lead a horse to water, but you can't make it drink. I tried.

I will probably be better off avoiding comments from somebody who flies off the handle like that.

It just baffles me that someone can provide page after page after page of proof to something so trivial- that a decrease in pressure decreases velocity, and that an increase accompanies an increase in velocity- yet it is rejected for no reason and that the person submitting the proof is yelled at.

[noisewaterphd]

Not one example of actual pressure testing a coated bullet to prove the pressure is lower and so is the velocity.

Lloyd, are you serious? You will never get that example because NOBODY ever said that. What was said is that a powder coated bullet creates slightly higher pressures, so goes slightly faster.

?

Unless you are talking about a moly coated bullet? In which case there are more examples available to your fingertips than you could ever read through.

[Echd]

I think the ambiguity stems from him talking about a "slicker" barrel, which isn't a very meaningful description, compared to a rougher one. The only way you can make this determination is through comparing identical chambers, throats, etc, not different barrels. However,as noted many, many times, one can apply coatings like molybdenum disulfide to a barrel's interior to make it slicker... and decrease velocity in the process. And also make an unholy mess! I doubt I will ever fool with moly coating again.

Not that it all matters... the science is settled, regardless.

[Smoke4320]

[QUOTE=noisewaterphd;3626440]Lloyd, are you serious? You will never get that example because NOBODY ever said that. What was said is that a powder coated bullet creates slightly higher pressures, so goes slightly faster.

Every report I have so far will all else being the same is about a 4% increase in speed PC over the exact same bullet lubed ..
Now for some people that means they will need to adjust their load a little to tweek accuracy .. As with every change in a load

[Stilly]

Has anyone tried taking a pc bullet and conventionaly lube sizing it? I wonder if at high velocitys (over 2k) if the addition of a good lube wouldn't help you get even more velocity before problems start.


LLOYD!

Correct me if I am wrong but the last time I saw you had said that you thought PC was stupid and you did not see the point to it. Maybe i got you mixed up with someone else. But it sounds like you might have found a color you like and are looking for a "practical" reason to get into PC, or at least a better reason then liking the color... ;)

Hmmm. I have not done what you are asking about. But I would not do it because I PC so that I do NOT have to deal with lube or star sizers or any of that mess.

BUT, Perhaps once you pc you can coat your pills in Moly or what is that white stuff? Boron Nitride something? BNH? BHN- yes, BHN I think it is called.

I do NOT know what it would do, but it might give you better results than lube would on account that that white BHN powder was supposedly slicker than moly which is supposed to be slicker than lube...

Whatever your choice, good luck and keep us posted.

[noisewaterphd]

Every report I have so far will all else being the same is about a 4% increase in speed PC over the exact same bullet lubed ..
Now for some people that means they will need to adjust their load a little to tweek accuracy .. As with every change in a load

Exactly what we are trying to get across here. And again, nobody is saying that is a bad thing, just that it happens.

[Lloyd Smale]

Smoke I will respond to you because I respect your opinion here. My point in all of this is friction never sped anything up it is drag. I just wanted to see ACTUAL testing the showed these bullets create more pressure because of more friction. My guess is they produce 4 percent more speed because theres less friction in the barrel not more. just like a smooth match quality rifle barrel will produce more fps then a rough pitted and corroded one.

Lots here had opinions but I haven't seen one actual pressure test or friction test to show these opinions are right. Guys are saying pressure rises but I seriously doubt if any of them have pressure testing equiptment to test them. Or do they have the lab testing equiptment to prove that these bullets create more or less friction then a cast bullet or a jacketed bullet. Again my common sense way of thinking tells me if a cast bullet will hold up to about 1500 fps without fouling a barrel and the same bullet coated will hold up to over 2000 fps without fouling the coated bullet has less friction.

Now I never once said I was dead right about this. I just asked for REAL PROOF and it seemed to offend some that I said they just weren't qualified ballistics experts when I guess they consider themselves so. Like I also said. I'm here to learn. But its not my first rodeo and Ive been around casting and shooting long enough to know theres some wives tales passed on all the time. I just wanted proof. REAL proof not opinion. I didn't want answers like "theres answers everywhere just look" or "its so obvious I don't have to show your proof" You see I'm not a ballistics expert, a gunsmith, a physics major or even good on a computer. I just wanted to make sense out of things that didn't look right to me. Ive just seen it to many times here. Read a few post, do a web search and cast a couple hundred bullets and I'm now an expert. My opinion now should be take like its wrote in stone.

Smoke I thank you for the help you've given me. You've answered every question ive asked with no bs or chest thumping as have some others. Stilly, yes I was the one that didn't have much use for this. I guess other then limited applications I still don't see it replacing my lube sizer but it is another avenue to pursue in this hobby. A hobby I take very seriously. When I do something like this my brain works and I just like to have REAL answers to my questions. Ive been wrong many times before. I'm the first to admit that. I was wrong in my opinion that this is a total waste of time. But now that I decided to give it a spin I want to do it right. that to me means more then putting a colored coating on a bullet and going to the range. I'm sorry if I offended SOME some not so much.
[QUOTE=noisewaterphd;3626440]Lloyd, are you serious? You will never get that example because NOBODY ever said that. What was said is that a powder coated bullet creates slightly higher pressures, so goes slightly faster.

Every report I have so far will all else being the same is about a 4% increase in speed PC over the exact same bullet lubed ..
Now for some people that means they will need to adjust their load a little to tweek accuracy .. As with every change in a load

[6bg6ga]

I got into it a while back in a thread about bullet lube and it wasn't pretty. There were those that conducted a lot of tests and they came to the conclusion that a certain amount of drag was needed in order to obtain maximum accuracy. Still don't know if I believe it or not but I threw it out there. I will throw my two cents in and see what happens. I tend to like real honest to goodness proof on paper. Got some ballistic info? I'd like to see some control groups. I'd like to see specific loads what speed was and accuracy spread. Also, where did the pressure info come from? Some of you must be very good and also own some good testing equipment.

First several control groups and then introduce the variables and again document the speed and accuracy spread. This in my opinion and is real honest to goodness proof. I can somewhat see the speed decrease in my mind but then again document it just for fun. As I mentioned before I got into it in a lube thread and thinking back on this it would tell me that accuracy might suffer since they hammered in the idea that a certain amount of drag was necessary for the best accuracy. So, show me what you got and make a believer out of me, otherwise I'm sorry but I won't buy into it without solid proof.

[Smoke4320]

Lloyd
As you have seen I only answer to what I know. Let others speculate. Pressure testing equipment would be nice but even then it really only applies to the exact guns and loads tested
We have achieved the goal in showing pc works in bullets and not get leading.
Actual pressure results may only come if federal or some other ammo mfg decides to publish their results
Now it could show trends but needs a good number of guns/loads tested to show the trend

[noisewaterphd]

Nevermind. Offer retracted.

I read back through the thread, and Lloyd, after some of your passive aggressive replies I am no longer willing to help you.

Good luck.

[noisewaterphd]

I got into it a while back in a thread about bullet lube and it wasn't pretty. There were those that conducted a lot of tests and they came to the conclusion that a certain amount of drag was needed in order to obtain maximum accuracy. Still don't know if I believe it or not but I threw it out there. I will throw my two cents in and see what happens. I tend to like real honest to goodness proof on paper. Got some ballistic info? I'd like to see some control groups. I'd like to see specific loads what speed was and accuracy spread. Also, where did the pressure info come from? Some of you must be very good and also own some good testing equipment.

First several control groups and then introduce the variables and again document the speed and accuracy spread. This in my opinion and is real honest to goodness proof. I can somewhat see the speed decrease in my mind but then again document it just for fun. As I mentioned before I got into it in a lube thread and thinking back on this it would tell me that accuracy might suffer since they hammered in the idea that a certain amount of drag was necessary for the best accuracy. So, show me what you got and make a believer out of me, otherwise I'm sorry but I won't buy into it without solid proof.

I can tell you with certainty that once you drop below a certain coefficient of friction, for a given weight, and given bearing length, your ES and SD will go wild.

This only translates into guaranteed degraded accuracy if you are shooting beyond your "zero", as it will vary the vertical POI.

I also don't know exactly 'why' this happens, just that it happens. I have my assumptions, but never dug into it much

If you are asking me for ballistics results regarding your specific question, the answer is maybe. It's a lot of work, and I usually have to do it after hours. Since I have no dog in your fight it will have to take a backseat.

[noisewaterphd]

BTW, anyone on this thread can test the relative friction of two projectiles in their own shop.

All you need is a push through sizer, a lubed bulled, a powder coated bullet, and any applicable measuring device (a hanging scale, maybe a trigger pull gauge, your own arm, etc).

Keep in mind that in the barrel the lube is basically rubbed all over the bullet by way of displacement and/or other measures. So for the the most realistic result you may want to tumble the lubed bullet.

[JimB..]

Will ya'll tolerate an sloppy analysis from a newbie? Just so you know, I've a passing familiarity with both physics and calculus, unfortunately I know nothing about fluid dynamics which is where the conversation is likely to go if we don't make a lot of simplifying assumptions. I'm intrigued by the (let's call it a hypothesis rather than any number of pejorative terms) that additional friction creates additional velocity.

First let's look at basic thermodynamics, you're producing a fixed amount of energy through combustion and it is used to expand the brass, heat the brass and receiver, accelerate the mass and overcome friction (please assume a sealed chamber). Common sense, which is not necessarily correct, seems to indicate that the only variables are friction and velocity and that using energy to overcome friction must reduce velocity given a fixed amount of energy.

Next if the same charge is used and the same amount of gas produced in both cases, but there is less pressure at a given time when there is less friction, then it must be because the volume is expanding more rapidly, right? The only way this is happening is if the bullet is traveling faster when there is less friction.

Now how about pressure. Just before the bullet exits the barrel the pressure must be the same regardless of friction. The volume available is fixed, and if the volume of gas produced is constant, then the pressure must be the same. The rate of change in pressure will be different, the faster the bullet the faster the pressure will be dropping because the volume is increasing more rapidly. Point is that pressure will be exactly the same when the mass is in the same position in the barrel regardless of the level of friction between the bullet and bore.

Finally if I accept that this has been tested and that within reasonable parameters modest increases in friction do tend to increase velocity, how do we explain this observation?

My guess is that the assumptions above about the same amount of energy being released and the same amount of gas being produced are incorrect. That powder burn rate tends to increase with increases in pressure, as does the completeness of the reaction, so additional friction between the barrel and bullet leads to the production of more energy from the same charge, and so long as the extra energy produced is greater than the extra energy used by friction, the bullet will exit the barrel at a higher velocity.

Seem reasonable?

It would be interesting to test this with a pneumatic gun where the volume of gas produced is easily controlled, I suspect that more friction would reduce velocity in that instance.

Hope you all have a good evening, the real point of my post was to distract me from troublesome issues at work, and I have assuredly accomplished at least that.

Jim

[noisewaterphd]

Will ya'll tolerate an sloppy analysis from a newbie? Just so you know, I've a passing familiarity with both physics and calculus, unfortunately I know nothing about fluid dynamics which is where the conversation is likely to go if we don't make a lot of simplifying assumptions. I'm intrigued by the (let's call it a hypothesis rather than any number of pejorative terms) that additional friction creates additional velocity.

First let's look at basic thermodynamics, you're producing a fixed amount of energy through combustion and it is used to expand the brass, heat the brass and receiver, accelerate the mass and overcome friction (please assume a sealed chamber). Common sense, which is not necessarily correct, seems to indicate that the only variables are friction and velocity and that using energy to overcome friction must reduce velocity given a fixed amount of energy.

Next if the same charge is used and the same amount of gas produced in both cases, but there is less pressure at a given time when there is less friction, then it must be because the volume is expanding more rapidly, right? The only way this is happening is if the bullet is traveling faster when there is less friction.

Now how about pressure. Just before the bullet exits the barrel the pressure must be the same regardless of friction. The volume available is fixed, and if the volume of gas produced is constant, then the pressure must be the same. The rate of change in pressure will be different, the faster the bullet the faster the pressure will be dropping because the volume is increasing more rapidly. Point is that pressure will be exactly the same when the mass is in the same position in the barrel regardless of the level of friction between the bullet and bore.

Finally if I accept that this has been tested and that within reasonable parameters modest increases in friction do tend to increase velocity, how do we explain this observation?

My guess is that the assumptions above about the same amount of energy being released and the same amount of gas being produced are incorrect. That powder burn rate tends to increase with increases in pressure, as does the completeness of the reaction, so additional friction between the barrel and bullet leads to the production of more energy from the same charge, and so long as the extra energy produced is greater than the extra energy used by friction, the bullet will exit the barrel at a higher velocity.

Seem reasonable?

It would be interesting to test this with a pneumatic gun where the volume of gas produced is easily controlled, I suspect that more friction would reduce velocity in that instance.

Hope you all have a good evening, the real point of my post was to distract me from troublesome issues at work, and I have assuredly accomplished at least that.

Jim

Yes. But, as you have already alluded to, there is indeed more to the story.

However, we do not believe in science here.

[Echd]

Jim, you sound like a guy who knows his stuff.

I agree completely with you, but would like to add a corollary to your statement- that while the muzzle velocity may suffer in a case of an extremely overlong barrel inducing drag (remember how CB caps warned against their use in long barrels at times due to fear the bullet would not exit?), that a maximum velocity can be reached for a given charge within the barrel that exceeds that of the muzzle velocity with an increasing pressure- but past an optimum barrel length determined by factors such as the volume of the bore, volume of propellant gas generated, and burn rate of the powder in question, drag will indeed reduce the muzzle velocity at that point.

That reminds me of an older anschutz 22 with a 29 or 30 inch barrel I used to shoot. Much bulk pack ammo was subsonic or right on the border of it through that barrel. However, clearly the ammunition was just as potent as it was in a 16 inch 10/22- but it was reaching its maximum velocity within the barrel, and that tipping point you alude to where the drag of the barrel outweighs the energy pushing that bullet had begun to set in.

I also think as it has been phrased that increased pressure brings increased velocity as has been stated is a bit of an unfair statement. The increased velocity is always accompanied by that increased pressure, but to say one causes the other is not necessarily true- they are instead attendant to one another. You can't have one side of an equation without the other of course!

So again I will make one modification to your statement regarding the pressure gun. If more friction were introduced through the means of more barrel length or bearing surface, it is possible that the maximum velocity may be reached WITHIN the bore while the actual muzzle velocity may be decreased- after all, no acceleration takes place after the bullet has left the barrel.

Now my question- does a friction increasing coating like powder coating move the equilibrium point (well, that is definitely not the right term... But rather the point of maximum efficiency) back in the barrel, allowing more fps with a shorter barrel? It seems it should. Following it to its logical conclusion it seems like being able to spike pressure as quickly as possible- potentially through added friction in coatings- can get us the speediest bullet in the shortest barrel.

[noisewaterphd]

This is true, but we are starting to take the argument out of context again, just a little bit.

Assuming well designed firearms, cartridges, and proper powder choices, a barrel long enough for friction to overcome pressure should absolutely be the exception (subsonic rimfire and suppressor specific ammo excluded, of course).

Plus, now we are venturing in to the fluid dynamics discussion that we said we would not.

[Echd]

Absolutely. We are reaching the point of discussing outliers to attempt to find fault with the more general themes, yet even these outliers obey the same rules- albeit in slightly less obvious ways.

Searching for the fastest round, after all, is rarely so important as the more accurate one.

[M-Tecs]

Never fired a PC bullet nor compared them to standard lubed bullets. I have chrono'd jacketed rifle bullets with moly, Hex Boron Nitrate and Danzac (Tungsten). In every case velocity decreased 50 to 100 FPS with the coated jacketed bullets. I don't have access to pressure testing equipment but both Norma and Serria do and they claim slipperier bullets equal lower pressure and velocity.

[JimB..]

Thanks for the kind words.

Unfortunately I do not have the background necessary to predict when a bullet will reach maximum velocity, other than to say that it must be before it exits the bore as stated by Echd. I think that to figure it out you'd construct a balanced force equation looking at not just the changing pressure and bullet to barrel friction, but the moment of inertia for the bullet and force to get the bullet out of the case. In the analysis the burn rate of the powder and completeness of the reaction become critical because they determine the pressure curve. Having said that, I believe that in general, pistol caliber bullets reach max velocity within the length of a carbine barrel while rifle caliber bullets make full use of barrel length.

By the way, a rough answer is not hard to obtained empirically. If you look around the web you'll see that there is a lot of data comparing velocity and barrel length, for example it has been observed that a 9mm 147 gr bullet reaches maximum velocity in 5" to 6". Obviously this ignores a bunch of factors including the one we're focused on here, but it's a starting point for additional testing.

Echd, to your last question about using a little friction to increase velocity from a shorter barrel, I don't know. While I can predict that the amount of energy produced must be variable based on friction, and that it will be higher with more friction, I don't know how the burn rate, efficiency and pressure curve change with additional resistance so can't predict acceleration at specific points in the barrel. You can obviously determine this for any specific load in any specific gun by changing the bullet coating and measuring the change in velocity, much faster than doing the math to be sure.

By the way, it occurs to me as I wake up that I may have used circular logic in my first post above. I said that I accept that folks have observed that when there is additional friction that there is additional velocity, but I don't know that the observers are certain that there is more or less friction from any particular lubricant or coating. Can someone tell me how you know that the coefficient of friction for PC is greater than for traditional lube? If the answer is because the velocity is higher, then I think we're chasing our tail. (Edit, just saw m-tecs post, looks like Sierra and Norma have worked this out, so all good.)

[JimB..]

I'm trying to explain the observations, not find fault with them.

[Lloyd Smale]

yup smoke, that's why in the short time ive delt with you you've earned my respect. You don't beat your chest and pretend to be something your not. Just good honest answers backed by REAL WORLD EXPERIENCE. :goodpost:
Lloyd
As you have seen I only answer to what I know. Let others speculate. Pressure testing equipment would be nice but even then it really only applies to the exact guns and loads tested
We have achieved the goal in showing pc works in bullets and not get leading.
Actual pressure results may only come if federal or some other ammo mfg decides to publish their results
Now it could show trends but needs a good number of guns/loads tested to show the trend

[Lloyd Smale]

don't remember asking:cry:
Nevermind. Offer retracted.

I read back through the thread, and Lloyd, after some of your passive aggressive replies I am no longer willing to help you.

Good luck.

[Spector]

This may or may not bear on this issue. If gravity were the constant force applied to accelerate these boolits in question toward earth instead of expanding hot gasses, then dropped simultaneously from the same height they would both fall at the same rate. If one of them were dropped through an oversize tube I suspect that bouncing against the walls of the tube and the friction created would slow that boolit down. As the size of the tube is reduced, more friction would occur further slowing down the boolit.

OK.....lets say hard lead round balls instead of boolits so the shape would remain constant going through the tubes. At some point as the tube diamenter is decreased the round ball will have so much friction impeding it gravity will not overcome it and the ball will simple not drop from the tube.

Double base smokeless powders are going to increase pressure fast the more a round ball is impeded if the tube becomes a barrel. So in this case friction serves to increase that propelling pressure......increasing velocity.

Gravity is pretty constant and friction is a detriment to the speed of a round ball in a tube. Friction can cause an increase in speed when the force applied comes from double base powders simply because the force is no longer constant.

Not sure, but I thought this might have some bearing on what you ''gentlemen'' are, ''at this point '' thankfully........''discussing''.

Mike

[JimB..]

This may or may not bear on this issue. If gravity were the constant force applied to accelerate these boolits in question toward earth instead of expanding hot gasses, then dropped simultaneously from the same height they would both fall at the same rate. If one of them were dropped through an oversize tube I suspect that bouncing against the walls of the tube and the friction created would slow that boolit down. As the size of the tube is reduced, more friction would occur further slowing down the boolit.

OK.....lets say hard lead round balls instead of boolits so the shape would remain constant going through the tubes. At some point as the tube diamenter is decreased the round ball will have so much friction impeding it gravity will not overcome it and the ball will simple not drop from the tube.

Double base smokeless powders are going to increase pressure fast the more a round ball is impeded if the tube becomes a barrel. So in this case friction serves to increase that propelling pressure......increasing velocity.

Gravity is pretty constant and friction is a detriment to the speed of a round ball in a tube. Friction can cause an increase in speed when the force applied comes from double base powders simply because the force is no longer constant.

Not sure, but I thought this might have some bearing on what you ''gentlemen'' are, ''at this point '' thankfully........''discussing''.

Mike

I believe that you are right as relates to gravity and the effect of friction between a vertical tube and a lead ball, but I think you're oversimplifying to the point of confusing others when it comes to how increased friction causes increased pressure and velocity.

Lloyd is not being very communicative, but he's right when he says that the barrel friction reduces velocity. All other things being equal the amount of friction does not affect pressure (pressure is a function of only the amount of gas produced and the volume it is limited to) and so increasing friction should reduce velocity. That experiments show that the opposite happens leads me to believe that all other things are not equal.

The thing most likely to change is the burn rate and completeness of the burn, I think we all have seen that powders tend to burn more completely when pressures are higher. So increased friction causes increased pressure (pretty early in the ignition phase) which causes the same charge to produce more gas more quickly, which causes the bullet to accelerate more rapidly when there is more barrel friction.

There are reasonable limits to this and at some point the increased friction would be great enough that the bullet would have lower velocity or may not even exit the barrel.

[M-Tecs]

barrel friction reduces velocity.

Not in all cases. As I stated above I have chrono'd jacketed rifle bullets with moly, Hex Boron Nitrate and Danzac (Tungsten). In every case velocity decreased 50 to 100 FPS with the coated jacketed bullets. I don't have access to pressure testing equipment but both Norma and Serria do and they claim slipperier bullets equal lower pressure and velocity.

[Echd]

I believe Spector's point was to compare a system where a constant force is applied versus one where the force is not constant (gravity, air or water pressure, etc vs a propellant charge or detonation).

The case friction isn't serving to increase the speed on its own... friction does indeed reduce velocity. BUT, the pressure must increase if a bullet is to travel faster. Or maybe it is more accurate to say that the peak pressure must be higher. It is pointless to compare one barrel to another, because while some bores are indeed "faster" than others (and a longer barrel will continue to contribute to velocity up to whatever nebulous point friction begins to outweigh the propellant gas), many seem to ascribe that to being because the bore is "tighter", the peak pressure is necessarily higher, and this outweighs the velocity which is robbed by friction and having the swage the bullet down that extra 0.0005 or whatever. That is tangential (but interesting and you will often see talk of it on PSR forums) and I don't want to derail further, as introducing too many variables is pointlessly confusing.

As Lloyd does point out an older barrel does tend to be "slower" than it was when new, and I will cite a source as to why (because it's for the exact opposite reason he believes)- from the Accurate Powders FAQ:

http://www.accuratepowder.com/faq/

What internal dimension of rifle caliber barrels affects internal ballistics the most?

The most critical dimensions are those immediately beyond the chamber/case mouth, known as the “Freebore” and “Leade”. This is where the engraving process takes place, which determines the level of resistance which in turn “controls” the combustion process.

This is also the area that experiences the highest and most severe forces and or conditions i.e. Peak-Acceleration, Peak- Pressure and Peak-Temperatures, therefore its also the area that experiences the most erosion and wear which ultimately leads to reduced velocities of a typical worn barrel.

Based on the information provided by accurate, where the bullet is "engraved" and the level of resistance is determined is where the combustion process is, as accurate helpfully uses quotation marks to show, "controlled". As the barrel is worn through high pressure and temperature, these dimensions are loosened, which results in the combustion process being "controlled" further down the bore, and where the propellant gas is given an accordingly larger area to peak, with an accompanying loss of velocity. Anyone who has shot a "barrel burner" has enjoyed the fruitless effort of "chasing the lands", where you have to continuously tweak your load out further and further if you want to stay at the same distance from the lands.

So to summarize (and hopefully simplify)

I would posit that the reason that reduced friction and greater slipperiness (within the same bore, mind, no matter how rough or clean that bore may be, comparing different bores would violate any semblance of having a control in your experiment) results in lower velocity because the pressure peaks further from the chamber, and therefore it peaks where there is more volume available for the expanding gas. Ergo, lower pressure and lower velocity, as the maximum velocity may (?) be mandated by the maximum peak pressure.

Bonus round and qualifier for previous statement:
Throwing an extra pointless complication in there I guess one could point out that an enormous charge of a faster powder could get a much higher peak pressure, like loading a 300 mag with red dot... maybe it would, but the gun wouldn't survive it to find out, and we are forced to work in the realm of feasibility... a slower powder reaches peak pressure more slowly, but is a necessity for the firearm to survive firing, and the larger volume of gas produced means more energy overall is generated. As lloyd incorrectly attempts to compare 2400 and titegroup, similar or identical pressures can be reached with accordingly different velocities, but when the slower powder is operating at the same pressures, it is doing so with a far greater volume of propellant, and therefore much more overall force and is better suited to moving larger bullets faster than a fast powder, which would quickly exceed safe pressures if the volume were increased so.

Please bear in mind also that according to Accurate Powders, peak chamber pressure occurs within the first 1.5-2 inches of most firearms. However, and this is to reiterate as I previously stated it once and do not want it taken out of context, barrel length will continue to increase velocity of the projectile until we reach that ephemeral "tipping point" where barrel friction and other velocity robbing factors outweigh the thrust imparted on the projectile by the expanding gasses.

My own personal question: can we achieve greater velocities through use of progressively burning powders or duplex charges? I am inclined to say mostly "no", but the idea of spreading out the peak pressure seems intriguing and the idea of using progressive, multiple detonations to launch a projectile HAS been done before- see https://en.wikipedia.org/wiki/V-3_cannon for an example. This is obviously far outside the realm of what we are discussing and does not change any of what we have- just an interesting personal aside and I am curious if there is a way to widen the peak pressure or if the only true solution is just to use a slower powder- which essentially maintains a higher average pressure. Is burn rate the only factor affecting the shape of a projectile's pressure curve or does chemistry also play a significant factor? These I do not know, but again we do have some real world examples of how people have tried to solve this problem... duplex charges and progressive multiple detonations. Neither could have been too successful and instead we just use slower powders for bigger boolits.

So to qualify, again and further, this requires a control- it is pointless and silly to compare dissimilar powders or barrels. Each barrel is going to be different, but they must all follow the rules which their own dimensions mandate.

I am aware there are some major oversimplifications in there and perhaps I have not articulated some points as well as I may have liked... but college physics and thermodynamics was a long time ago and writing this stuff feels very stream of consciousness to me now. Given that I went into comp sci and poli sci and spend my workdays arresting people instead, I'm not sure why I took them anyway... probably to argue with people on the internet.

An interesting aside and for the general interest:

http://closefocusresearch.com/calculating-barrel-pressure-and-projectile-velocity-gun-systems

Features a spreadsheet where one can make a simplified comparison between loads where you input the barrel and bullet's parameters along with a pressure to get an estimated velocity. The interesting factor that makes it relevant to this discussion is that one can vary the coefficient of friction measurement. Reducing the coefficient of friction will increase the velocity.... BUT it only does this at the same pressure value, and as reducing friction reduces pressure per Sierra, Nosler, Norma, Accurate, etc ... you are essentially chasing your own tail at that point. I just thought it was a fun spreadsheet and was just looking for an equation to illustrate pressure relative to velocity in a barrel. I do not believe there is a good way to effectively model the friction as there are no discrete units we can use to quantify it, especially without a control and way to test, and we would also need to pressure test each load and chrono it at the same time...

(side note: the spreadsheet has no way to automatically reduce pressure based on the value you enter for coeff of friction... both pressure and coeff of friction are independent variables you control and not dependents, therefore it is actually useless to the main part of this discussion... just interesting)

[JimB..]

Not in all cases. As I stated above I have chrono'd jacketed rifle bullets with moly, Hex Boron Nitrate and Danzac (Tungsten). In every case velocity decreased 50 to 100 FPS with the coated jacketed bullets. I don't have access to pressure testing equipment but both Norma and Serria do and they claim slipperier bullets equal lower pressure and velocity.

You missed my point, and you've taken that phrase out of context, but I could have said that better. Try this, all other things being equal, barrel friction will reduce velocity. If you disagree please reread my earlier two posts and tell me where you think I've erred, I'm sincerely trying to understand.

To be clear, I believe that what you are relating from Norma and Sierra is 100% accurate, and it's only because you provided this info and that I believe it that I feel confident saying that all other things must not be equal, even in the tests performed by Sierra and Norma. As I said above, I'm trying to explain the evidence you provided, that reducing friction reduces velocity, not refute it.

In short, I believe THAT you are right, that increased friction (within reasonable limits) does result in increased velocity, I'm trying to understand and explain WHY you are right.

[Echd]

I'm trying to understand and explain WHY you are right.

I would posit that the reason that reduced friction and greater slipperiness (within the same bore, mind, no matter how rough or clean that bore may be, comparing different bores would violate any semblance of having a control in your experiment) results in lower velocity because the pressure peaks further from the chamber, and therefore it peaks where there is more volume available for the expanding gas.

This is my hypothesis, removed from my horrendous blob of text. What do you think? I am not claiming it is the absolute right reason... but anyone who has tried moly coat, HBN, or other proven friction reducing compounds (lubricants seems like the wrong word here, but they really are just dry lubes, I guess) and chronographed it has seen velocities reduced.

[JimB..]

Echd, good post and thanks for bringing more useful information into the discussion.

However, I can't yet get behind the argument that "the reason that reduced friction and greater slipperiness...results in lower velocity because the pressure peaks further from the chamber, and therefore it peaks where there is more volume available for the expanding gas." Because it doesn't explain why the bullet is further from the chamber at peak pressure. It must assume that the bullet initially accelerates faster and to a higher velocity in the first couple inches, how else to get it further from the chamber in the same time, and then accelerates more slowly for the rest of the length of the barrel without explaining that either. It might be correct, but we need to think about how to close those holes. Of course with a high speed camera and a fluoroscope we could have a lot of fun figuring this out, wonder if we can get a government grant?

I admit that pointing to the burn characteristics of the powder is a lot like saying that it's magic, but I'm gonna stick with it for now.

I do have an airforce pellet gun, if anyone has cast solid .22 cal pellets I could probably do a pretty good job of eliminating the powder as a variable and see what happens to velocity with different lubes. Probably not worth doing as I think we all agree that without some variable around how the pressure is generated (either burn characteristics or other volumetric differences) that more bore friction will reduce velocity.

BTW, I left science and engineering for accounting, but I held onto some of the knowledge so I could help get my daughters through HS calc and physics, never knew that it'd be useful for gun forum discussions.

[JimB..]

On reconsideration, reduced friction would allow the bullet to travel the first couple inches more quickly...need to think a bit more.

[Echd]

You are right (or may be right, I have no idea!), and I did not consider it in this manner.

I do think there are other questions we might need to consider to get to the bottom of it.

Why do pressures peak? Is it purely a function of the powder, it's chemical makeup, and the burn rate (leading towards your theory)? Is it because of the projectile "bottling" the explosion (leading towards mine)? If we were to load a case with tissue paper for a fireforming load, where would the pressure peak? Where would it peak relative to a crimped bullet? A bullet loaded into the lands? What is the velocity of an unladen swallow?

Is the movement of a bullet necessarily smooth, or is it jerky in nature (I have NO IDEA about this. common sense seems to say smooth movement, but at the same time, if a bullet were "jerky" and allowed pressure to peak... that would provide a convenient answer). I do not want to take anything for granted with regards to this.

We do know that certain projectiles, even made of the same material, result in more pressure. A longer bearing surface, even on a bullet of the same weight, will tend to generate more pressure (because... more friction).

This post was mainly to pose questions to which I really do have no great answer.

Here is some additional reading that may help us draw some conclusions on why pressure curves look like they do, and what we can do to influence them and resulting velocity, even without changing the powder charge at all:

http://www.hornady.com/ballistics-resource/internal

To wit, I would like to examine bullet seating depth, a known method by which to vary chamber pressure. I have highlighted the most interesting section. It does discuss letting a bullet get a "running start" versus seating it evening against the rifling, and how that affects velocity, as well as pressure. This may or may not be perfectly germane to the topic at hand.



To illustrate the effects of variations in bullet travel before the bullet enters the rifling, we'll compare a standard load with adjustments made only in the bullet's seating depth.
In a "normal" load with the bullet seated to allow about one 32nd of an inch gap (A) between the bullet and the initial contact with the rifling, pressure builds very smoothly and steadily even as the bullet takes the rifling. Pressure remains safe throughout the powder burning period (B), and the velocity obtained - 3500 fps - is "normal" for this load in this rifle.
Seating the bullet deeper to allow more travel before it takes the rifling, as in these next two illustrations, permits the bullet to get a good running start (C). Powder gases quickly have more room in which to expand without resistance, and their pressure thus never reaches the "normal" level. Nor does the velocity; with the same powder charge it only comes to 3400 fps (D).
When the bullet is seated to touch the rifling, as in the accompanying illustrations, it does not move when the pressure is low (E); and not having a good run at the rifling as did the other bullets, it takes greatly increased pressure to force it into the rifling. As the rapidly expanding gases now find less room than they should have at this time in their burning, the pressure rise under these conditions is both rapid and excessive (F). Velocity is high at 3650 fps - but at the expense of rather dangerous pressure. Many rifles deliver their best groups when bullets are seated just touching the rifling. Seating bullets thus can be done quite safely if the reloader will reduce his charge by a few grains. The lighter load will still produce the "normal" velocity without excessive pressure.

[Echd]

Further reading:

http://www.rimworld.com/nassarocketry/pdfs/031-PROPELLANT%20PROPERTIES.pdf

This is an important snippet that answers my previous question as to why pressures peak. It also talks about how powder burn rate is measured, and states rather emphatically that it cannot be computed, only measured- which is interesting and something I did not know.


The results of measurements made in these ways show that the rate of burning of apropellant depends markedly on the pressure. At the high pressures used in guns(perhaps 20 tons/in2) it is often sufficient to assume that the rate of burning, R. isdirectly proportional to the pressure, p.

If the rate of burn is dependent on pressure, and greater pressure is found with more friction, then it is possible (plausible?) that the relationship between the two allows for greater friction to allow for higher velocities (massive oversimplification of course!!!) At some point the dynamic is such that the pressure has peaked- and this will vary based on the intrinsic qualities of the powder, the quantity of powder, and the area of the bore (maybe?). But as a result, the lower friction due to a friction reducing compound could mean that the powder is burning at a different rate and with an accordingly different pressure and maximum velocity.

[JimB..]

Echd, that is interesting.

I'm on an iPad, so I'll need to look at their info from the computer later, but isn't it counterintuitive that reducing OAL will reduce pressure? I also think that I disagree with their statement that "powder gases quickly have more room in which to expand without resistance." Isn't that space essentially the capacity of the cartridge below the base of the bullet at the moment the bullet engages the rifling, and therefore the same in all examples? I need to look at in more context, the wording may just not be perfectly clear to me.

I found this article interesting http://www.sadefensejournal.com/wp/?p=1093, but it is far less thorough than the Hornady info you linked to.

About your earlier question about progressive powders or duplex charges, I was thinking about the engineering for it and moved the charged from the cartridge to the rear of the projectile to efficiently enable constant thrust before I realized that you just invented a rocket.

And finally, and most importantly, an African or European swallow?

[JimB..]

Your post #69 pretty much wraps this up I think, or at least you and I have gotten to the same place.

[Echd]

That sounds good to me and it was an interesting discussion that raised some points I had never considered.

One last snippet regarding velocity, pressure, and friction reduction before I go to bed:

https://www.shootingsoftware.com/moly.htm


As bore friction is reduced, the bullet may accelerate down the bore as if it has lighter mass. This can result in secondary pressure spikes if the powder is barely fast enough for the bullet's rate of acceleration.

Of note is the statement that statea bullets with lower friction coatings act as if they are lighter than they are, and may be able to outrun the powder so to speak. That heavily implies that their acceleration may in the earliest stages outpace a normal or more frictive bullet of the same design, with resulting overall lower pressure and velocity as the powder charge never built up a full head of steam.

[noisewaterphd]

OK, so you are actually both correct.

Friction has an effect on gas burn, but, believe it or not it does change bullet travel time enough to have an effect as well.

This happens because bullet friction changes what we call "shot start pressure". Basically this is the same reason it takes less powder to move a heavier bullet, instead of more powder.

Let's use a 454 Casull with an NOE 454-350 GC 350gr bullet, seated at 1.700 over 24gr Ramshot Enforcer in a 6.5" barrel for example.

Bullet #1 is powder coated:

max pressure: 59,652 psi

velocity: 1457 fps

powder burn: 98.68%

barrel time: (10% pmax to muzzle) .546ms
With this bullet we reach maximum pressure when the bullet has traveled .336"


Bullet #2 is lubed and tumble lubed cast with my homebrew lubes:

max pressure: 58,982 psi

velocity: 1449 fps

powder burn: 98.64%

barrel time: (10% pmax to muzzle) .549 ms

With this bullet we reach maximum pressure when the bullet has traveled .343"


So, as you can see, both are factors.

This is real world data, accompanied by standard calculations for powder burn/barrel time etc..

[noisewaterphd]

Echd, that is interesting.

I'm on an iPad, so I'll need to look at their info from the computer later, but isn't it counterintuitive that reducing OAL will reduce pressure? I also think that I disagree with their statement that "powder gases quickly have more room in which to expand without resistance." Isn't that space essentially the capacity of the cartridge below the base of the bullet at the moment the bullet engages the rifling, and therefore the same in all examples? I need to look at in more context, the wording may just not be perfectly clear to me.

I found this article interesting http://www.sadefensejournal.com/wp/?p=1093, but it is far less thorough than the Hornady info you linked to.

About your earlier question about progressive powders or duplex charges, I was thinking about the engineering for it and moved the charged from the cartridge to the rear of the projectile to efficiently enable constant thrust before I realized that you just invented a rocket.

And finally, and most importantly, an African or European swallow?


Jim, it really depends on how close the bullet is seated to the lands, and how much case capacity is available.

It is very common in high power rifles to have a reduced OAL actually reduce pressure. The closer you seat a bullet to the lands, the more shot start pressure is increased.

[Lloyd Smale]

I guess my uneducated thoughts are that Pressure will increase with an increase in friction but will only increase enough to overcome that friction. kind of like cruise control on your car. Set it at 60 and increase friction and the motor puts out just enough more hp to overcome that friction. I cant see how, for you physics majors (every action creates an EQUAL and opposite reaction) It doesn't create an increased reaction. I would have to think that if friction was increased so much as to have the effect of increasing pressure. The point that pressures went high enough up to effectively increase velocity measurably in that bad barrel with its increased friction would probably have you in a very dangerous pressure range.

Also I was thinking back on my own experiences trying to remember one that fit and this happened one day. Granted its an extreme example. Back years ago when I shot at a public range I had my first chronograph set up. It was an old ohler and it was rare to see one around here then and lots of guys wanted to try it when I had it out. I was there early one morning and there was only one other shooter. A guy with a 44 5.5 inch redhawk. He was shooting at the 25 yard target and wasn't even hitting the target every time. It kind of got my attention and I asked him If I could try it with my loads. He gave me the gun and I shot it (I had the chrono set up in front of me) I don't remember the load but it was a mid range cast bullet load. His gun was showing about 75 fps less then mine and I was shooting a 4 5/8s super with a shorter barrel. First thing I thought was it is just a different gun and ive seen it before where a shorter barrel produced more velocity then a long one. Thing is I couldn't do any better then about 8 inchs at 25 yards with my load and his gun.

So I knew something was wrong. I then noticed that both his and my ammo was showing flattened primers. I know that some redhawks had a bad constriction at the frame. First thought was that this gun was so bad that it was choking down the bullets so bad that gases were just blowing by and not pushing the bullet. Well I opened it up and looked down the bore and it was plugged SOLID with lead. Come to find out he had bought a box of a 1000 pure lead swadged bullets and shot them with top end book magnum loads. Now I never saw what happened after he cleaned it but at the time I sure thought the plugged barrel was why it shot slower. I have to doubt that after it was cleaned it would have shot slower yet. Again this was only one example of ONE gun. Ive seem some strange things in my years of shooting so even what I see with my own eyes once in a while has fooled me.

[Lloyd Smale]

you talking 8fps and less the 700psi (which is less then 2%)pressure increase. I challenge you to come up with a load that has less standard deviation. At 8fps difference I would have to call it a non issue if nothing else. Ive shot 454s for about 20 years and will say without reservation that ive never had a load that gave under 20fps standard deviation with small rifle primers. I have got in down around 10 fps with 460 brass with larger primers cut down to 454 length. Thank you though for the real world data. That's what I'm looking for But like I said it about proves this is a non issue.
OK, so you are actually both correct.

Friction has an effect on gas burn, but, believe it or not it does change bullet travel time enough to have an effect as well.

This happens because bullet friction changes what we call "shot start pressure". Basically this is the same reason it takes less powder to move a heavier bullet, instead of more powder.

Let's use a 454 Casull with an NOE 454-350 GC 350gr bullet, seated at 1.700 over 24gr Ramshot Enforcer in a 6.5" barrel for example.

Bullet #1 is powder coated:

max pressure: 59,652 psi

velocity: 1457 fps

powder burn: 98.68%

barrel time: (10% pmax to muzzle) .546ms
With this bullet we reach maximum pressure when the bullet has traveled .336"


Bullet #2 is lubed and tumble lubed cast with my homebrew lubes:

max pressure: 58,982 psi

velocity: 1449 fps

powder burn: 98.64%

barrel time: (10% pmax to muzzle) .549 ms

With this bullet we reach maximum pressure when the bullet has traveled .343"


So, as you can see, both are factors.

This is real world data, accompanied by standard calculations for powder burn/barrel time etc..

[JimB..]

https://www.shootingsoftware.com/moly.htm

Of note is the statement that statea bullets with lower friction coatings act as if they are lighter than they are, and may be able to outrun the powder so to speak. That heavily implies that their acceleration may in the earliest stages outpace a normal or more frictive bullet of the same design, with resulting overall lower pressure and velocity as the powder charge never built up a full head of steam.

Hadn't considered this, but it makes sense that the bullet could be over accelerated at an early point in the burn. It has been a good discussion, thank you much.



OK, so you are actually both correct.

Friction has an effect on gas burn, but, believe it or not it does change bullet travel time enough to have an effect as well.

This happens because bullet friction changes what we call "shot start pressure". Basically this is the same reason it takes less powder to move a heavier bullet, instead of more powder.

Let's use a 454 Casull with an NOE 454-350 GC 350gr bullet, seated at 1.700 over 24gr Ramshot Enforcer in a 6.5" barrel for example.

Bullet #1 is powder coated:

max pressure: 59,652 psi

velocity: 1457 fps

powder burn: 98.68%

barrel time: (10% pmax to muzzle) .546ms
With this bullet we reach maximum pressure when the bullet has traveled .336"


Bullet #2 is lubed and tumble lubed cast with my homebrew lubes:

max pressure: 58,982 psi

velocity: 1449 fps

powder burn: 98.64%

barrel time: (10% pmax to muzzle) .549 ms

With this bullet we reach maximum pressure when the bullet has traveled .343"


So, as you can see, both are factors.

This is real world data, accompanied by standard calculations for powder burn/barrel time etc..

Makes perfect sense. May I ask what part of the data is measured and what is based on standard calculations? While Echd and I are discovering how this works for ourselves, I think we both recognize that the science is well developed, so I'm not challenging the calculations, just wondering what the inputs are. Echd referred to a spreadsheet that did similar calculations, but as I recall it didn't incorporate bullet coating data.

Also, do you work in the industry?


Jim, it really depends on how close the bullet is seated to the lands, and how much case capacity is available.

It is very common in high power rifles to have a reduced OAL actually reduce pressure. The closer you seat a bullet to the lands, the more shot start pressure is increased.

This makes perfect sense, I just hadn't thought it through before.


I guess my uneducated thoughts are that Pressure will increase with an increase in friction but will only increase enough to overcome that friction. kind of like cruise control on your car. Set it at 60 and increase friction and the motor puts out just enough more hp to overcome that friction. I cant see how, for you physics majors (every action creates an EQUAL and opposite reaction) It doesn't create an increased reaction. I would have to think that if friction was increased so much as to have the effect of increasing pressure. The point that pressures went high enough up to effectively increase velocity measurably in that bad barrel with its increased friction would probably have you in a very dangerous pressure range.

Also I was thinking back on my own experiences trying to remember one that fit and this happened one day. Granted its an extreme example. Back years ago when I shot at a public range I had my first chronograph set up. It was an old ohler and it was rare to see one around here then and lots of guys wanted to try it when I had it out. I was there early one morning and there was only one other shooter. A guy with a 44 5.5 inch redhawk. He was shooting at the 25 yard target and wasn't even hitting the target every time. It kind of got my attention and I asked him If I could try it with my loads. He gave me the gun and I shot it (I had the chrono set up in front of me) I don't remember the load but it was a mid range cast bullet load. His gun was showing about 75 fps less then mine and I was shooting a 4 5/8s super with a shorter barrel. First thing I thought was it is just a different gun and ive seen it before where a shorter barrel produced more velocity then a long one. Thing is I couldn't do any better then about 8 inchs at 25 yards with my load and his gun. So I knew something was wrong. I know that some redhawks had a bad constriction at the frame. First thought was that this gun was so bad that it was choking down the bullets so bad that gases were just blowing by and not pushing the bullet. Well I opened it up and looked down the bore and it was plugged SOLID with lead. Come to find out he had bought a box of a 1000 pure lead swadged bullets and shot them with top end book magnum loads. Now I never saw what happened after he cleaned it but at the time I sure thought the plugged barrel was why it shot slower. I have to doubt that after it was cleaned it would have shot slower yet.

First recognize that things come apart at the extremes, and that the extremes are never far away. The revolver with a heavily leaded bullet will likely be slower than the same bullet through that revolver with a clean barrel. First, it's a revolver and the pressure losses between the cylinder and barrel may have a greater effect on velocity than barrel friction. Second, the example is too extreme, it's pushed the cartridge outside its normal operating parameters.

With cruise control when you hit the target speed the computer stops accelerating, with the powder burn there is no limiter beyond the size of the charge and the speed of the powder, but if you keep those the same the pressure builds higher, above the normal range, because the bullet's movement is restricted. The effect is rather small and I think easily offset by things like a cruddy barrel or throat erosion.

[MostlyLeverGuns]

Smooth or rough? Tight or loose ? Fast or slow? Every barrel makes its own rules. Chamber dimensions, throat dimension, tight spots, loose spots, taper, reverse taper make every barrel different. Only approximations of what will happen can be made. Most who reload for more than one rifle of a caliber realize that it is unusual when the same loads work for TRUE PRECISION. We are not talking beer cans at 20 yards here. 10 grains of Unique might/should be OK in a bunch of rifles - it is probably not the best load in any of them. Your firearm is unique, only careful testing for accuracy and velocity IN THAT FIREARM will answer your question - the rest is just general information or educated guessing.

[Spector]

If I am understanding correctly resistance to movement by a boolit can cause smokeless powders to burn faster and more completely. This resistance can be caused by increasing boolit weight, seating a boolit into the barrel lands or by frictional resistance. And resistance is only beneficial to velocity until maximum pressure is reached. From that point on frictional resistance becomes and impediment to velocity.

In theory if a boolit coating were developed that would offer resistance to movement it would maximize powder efficiency. If that same coating lost it's frictional property once accelerated with the boolit then velocity would be more easily maintained for the remaining distance through the barrel as long as the boolit diameter continued to efficiently seal gasses behind it in the bore until it exited the muzzle.

So what are the properties of the lubes and coatings we now use on our boolits? If they do not leave deposits in our barrels then boolit diameter should be maintained thus efficiently sealing in the propelling gasses.

My next question is.....do any of our lubes/coatings become slicker from the frictional heat generated or from the burning gasses behind it as peak pressure is reached?

I would think that in a seasoned bore that alox or relatively hard conventional lubes would provide some resistance with increasing lubricity as the boolit travels the bore.

In the case of properly cured powder coat I am afraid to even venture a guess. I suspect a seasoned bore is not necessary and wonder in our search for better coatings and lubes, especially for rifles, what advantages might be provided.

I wonder for instance if powder coat remains constant in it's lubricity as it travels a rifle barrel or if it may somehow get slicker as the trip progresses especially after peak pressure is reached.

I hope this doesn't just muddy the discussion even more, but that is the direction my brain has turned after reading this increasingly interesting discussion.

Theory is fine as it aids understanding. Even if a coating/lube were to produce friction to aid powder burn and more lubricity once maximum pressure is reached the minuscule gained benefits may be no better than a theoretical advantage. Seating depth and seating into the lands I suspect will always have more affect masking any real attempt to judge the efficiency of coatings beyond leaving a relatively clean bore and enhancing accuracy. And I suspect any benefits will not affect throat erosion much either.

A clean bore and accuracy will be good enough for me any day. As I get older I find it is less important for me to understand why or how. Just which product or technique is the better. Even increasing velocity is seeming more and more counter productive to me anymore. And easy barrel clean up is even more important. Paper patching gave me that. Hopefully powder coating will give me that with much less manual dexterity needed in these arthritic fingers. grin

Mike

[Lloyd Smale]

boy if this shouldn't be wrote in stone!!!!!!!!
Smooth or rough? Tight or loose ? Fast or slow? Every barrel makes its own rules. Chamber dimensions, throat dimension, tight spots, loose spots, taper, reverse taper make every barrel different. Only approximations of what will happen can be made. Most who reload for more than one rifle of a caliber realize that it is unusual when the same loads work for TRUE PRECISION. We are not talking beer cans at 20 yards here. 10 grains of Unique might/should be OK in a bunch of rifles - it is probably not the best load in any of them. Your firearm is unique, only careful testing for accuracy and velocity IN THAT FIREARM will answer your question - the rest is just general information or educated guessing.

[Lloyd Smale]

which brings up another thought in my uneducated mind. If friction causes pressure to increase velocity to any extent. Wouldn't a string of rifle shots using jacketed bullets get faster and faster every shot due to the increased friction caused by the hot steel. If I then shot a 5 shot group wouldn't the first shot cold barrel be much lower velocity then the next and wouldn't the last one always be the fastest unless a guy sat and waited patiently after every shot till the barrel cooled to ambient temperature.

This is something ive surely never noticed in 40 years of chronographing rifles and handguns with jacketed and cast. Back to rifles again. Ive shot the x bullets boated coated and non coated. Why is it in my guns the coated bullets were a 50-100 fps faster? Now barnes advertises the coating as an anti friction coating. For the most part I think I nailed it in the post above. This is a NON ISSUE. It doesn't make enough of a difference where an increases or decrease in speed as small as it causes couldn't be blamed on, and very like BE caused by something else. When your talking under a 5 percent change something as insignificant as the temp outside or a slight difference in crimp, different lot of powder, different brand of primer all could cause it. I think its more then anything something for the wanabe physics professors to talk about using big words and technical terms trying to impress us all. Problem is theres to many holes in the equations and not enough in there targets. [smilie=l::redneck:
If I am understanding correctly resistance to movement by a boolit can cause smokeless powders to burn faster and more completely. This resistance can be caused by increasing boolit weight, seating a boolit into the barrel lands or by frictional resistance. And resistance is only beneficial to velocity until maximum pressure is reached. From that point on frictional resistance becomes and impediment to velocity.

In theory if a boolit coating were developed that would offer resistance to movement it would maximize powder efficiency. If that same coating lost it's frictional property once accelerated with the boolit then velocity would be more easily maintained for the remaining distance through the barrel as long as the boolit diameter continued to efficiently seal gasses behind it in the bore until it exited the muzzle.

So what are the properties of the lubes and coatings we now use on our boolits? If they do not leave deposits in our barrels then boolit diameter should be maintained thus efficiently sealing in the propelling gasses.

My next question is.....do any of our lubes/coatings become slicker from the frictional heat generated or from the burning gasses behind it as peak pressure is reached?

I would think that in a seasoned bore that alox or relatively hard conventional lubes would provide some resistance with increasing lubricity as the boolit travels the bore.

In the case of properly cured powder coat I am afraid to even venture a guess. I suspect a seasoned bore is not necessary and wonder in our search for better coatings and lubes, especially for rifles, what advantages might be provided.

I wonder for instance if powder coat remains constant in it's lubricity as it travels a rifle barrel or if it may somehow get slicker as the trip progresses especially after peak pressure is reached.

I hope this doesn't just muddy the discussion even more, but that is the direction my brain has turned after reading this increasingly interesting discussion.

Theory is fine as it aids understanding. Even if a coating/lube were to produce friction to aid powder burn and more lubricity once maximum pressure is reached the minuscule gained benefits may be no better than a theoretical advantage. Seating depth and seating into the lands I suspect will always have more affect masking any real attempt to judge the efficiency of coatings beyond leaving a relatively clean bore and enhancing accuracy. And I suspect any benefits will not affect throat erosion much either.

A clean bore and accuracy will be good enough for me any day. As I get older I find it is less important for me to understand why or how. Just which product or technique is the better. Even increasing velocity is seeming more and more counter productive to me anymore. And easy barrel clean up is even more important. Paper patching gave me that. Hopefully powder coating will give me that with much less manual dexterity needed in these arthritic fingers. grin

Mike

[Echd]

Proven incorrect after insulting others, yet continues with insults even so. I only hope that I am never so childish!

[JimB..]

Smooth or rough? Tight or loose ? Fast or slow? Every barrel makes its own rules. Chamber dimensions, throat dimension, tight spots, loose spots, taper, reverse taper make every barrel different. Only approximations of what will happen can be made. Most who reload for more than one rifle of a caliber realize that it is unusual when the same loads work for TRUE PRECISION. We are not talking beer cans at 20 yards here. 10 grains of Unique might/should be OK in a bunch of rifles - it is probably not the best load in any of them. Your firearm is unique, only careful testing for accuracy and velocity IN THAT FIREARM will answer your question - the rest is just general information or educated guessing.

I agree, if someone is only concerned that something works, then simple experimentation will get there with the least amount of effort. That's not at all what we've been discussing.

Accepting the evidence presented, that bullets with coatings that are known to have lower friction have lower velocity when loaded the same, our discussion has been about figuring out why this is true. I don't think that having worked out the why of it will make me a better shooter, and I'm surely not going to try to create some formula for applying this to future loads when trial and error does the job more efficiently, I simply enjoy learning the why of things.

Lloyd has been vacillating between questioning if the evidence is correct and deciding if the effect is meaningful even if the evidence is correct, both good questions. In the end he'll end up where you are, knowing that it really doesn't matter for what a long range shooter is trying to accomplish.

[JimB..]

Spector, rather than try to answer your questions directly may I simply say that I think you share the understanding I have except that I think velocity is determined by both peak pressure and average pressure. I believe this because the bullet continues to accelerate long after pressure has peaked and because, as Echd pointed out, it is possible for the bullet to be pushed too far ahead of the combustion gases causing a pressure drop and reduced velocity.

As for changing lubricity, I'm confident that it happens because high temps do that sort of thing, but I have no specifics. For my purpose I think maximum consistency would come from having the bullet "coast" in the barrel for only a very short time. Once it stops accelerating the barrel friction drops to zero because the bullet has exited the barrel, this eliminates any benefit of a barrel with higher lubricity at the muzzle and lower lubricity at the breech.

[noisewaterphd]

It doesn't really matter. It is just good to be aware of it, and understand it.

Working with max pressures, chasing single digit ES, or looking for the perfect load.

Not understanding how your gun works, or worse yet, believing the exact opposite is never going to help you. At what point does it get somebody hurt?


Lloyd, you haven't nailed anything except how to dig yourself a larger hole.

From this point forward, I basically assume anything you say is the opposite of reality.

[noisewaterphd]

Smooth or rough? Tight or loose ? Fast or slow? Every barrel makes its own rules. Chamber dimensions, throat dimension, tight spots, loose spots, taper, reverse taper make every barrel different. Only approximations of what will happen can be made. Most who reload for more than one rifle of a caliber realize that it is unusual when the same loads work for TRUE PRECISION. We are not talking beer cans at 20 yards here. 10 grains of Unique might/should be OK in a bunch of rifles - it is probably not the best load in any of them. Your firearm is unique, only careful testing for accuracy and velocity IN THAT FIREARM will answer your question - the rest is just general information or educated guessing.

We aren't comparing barrels. We are comparing bullets. The rule we are talking about applies to those bullets in all barrels.

[Lloyd Smale]

Don't like real world results as much as what they taught you in college? That's ok just another one to ad to the ignore list and id suggest the rest of you that think I have nothing to contribute to the world of cast bullets do the same to me. Its just a mouse click away and I know you learned that in school. You say I'm wrong but the best argument you come up with is an 8fps difference in velocity!!! that bud is not even enough of a difference to a real ballistics expert. [smilie=l: The best thing you could do is spend a second and read Mostlyleverguns last post. He said more in that short paragraph that is FACT then you have in this whole thread. Pay attention. You might learn something. :killingpc
We aren't comparing barrels. We are comparing bullets. The rule we are talking about applies to those bullets in all barrels.

[noisewaterphd]

MostlyLeverGuns posted a paragraph that had nothing to do with the topic at hand.

The fact that you feel it somehow refutes reality is interesting though, please do explain it to us. This should be entertaining.

[Lloyd Smale]

It would be cool if a couple of you went here http://castboolits.gunloads.com/showthread.php?305181-what-do-you-do-or-did-you-do-for-a-living/page11 I'm extreamly curious what you do. I sure is something cool like a brain surgeon. But then your on my ignore list so I wouldn't see your answer anyway.

[noisewaterphd]

I feel sorry for you Lloyd. Pushing the ignore button on anybody that might teach you something?

I'm sorry we confused you. But don't let fear get in the way of knowledge.

[No_1]

Stay on topic - cut out the nonsense and insults or this one will be locked with infractions issued.

R.

[firefly1957]

Lloyd I have fired some Lyman 45 bullets i coated and lubed,coated and sized and sized and lubed normally same alloy from my 45 acp all loads were 5 grains red dot CCI large pistol primer velocities were the same within reason the same happened when the cast coated bullets were swaged same velocity a bit better accuracy and less losses from scrapping coating off.
* On a side note cases with small pistol primers same coated sized bullets 5 grains Red Dot ran 30 fps slower and had a much wider standard deviation and poorer accuracy.

[JimB..]

Lloyd I have fired some Lyman 45 bullets i coated and lubed,coated and sized and sized and lubed normally same alloy from my 45 acp all loads were 5 grains red dot CCI large pistol primer velocities were the same within reason the same happened when the cast coated bullets were swaged same velocity a bit better accuracy and less losses from scrapping coating off.
* On a side note cases with small pistol primers same coated sized bullets 5 grains Red Dot ran 30 fps slower and had a much wider standard deviation and poorer accuracy.

The differences we're talking about are small, I'm not surprised that they are less than the normally observed variations seen from a pistol or revolver. I'm pretty confident that they would be detectable from a long-range bolt gun either as a reduction in velocity or a change in the poi. Would really like it if Lloyd would volunteer to do the test using commercial or cast .308 that are identical other than coatings. I'd chip in.

At the risk of going off topic, I sort 45acp brass by primer size and only load the large, small is kept in case of future shortages of brass or LPP.

[M-Tecs]

Interesting test here http://www.sprinco.com/testresults.html

Velocity Change With Moly Coated Bullets Vs Moly Weapons Oil
By: Dick Hatfield

Recently I became aware of a product called Spica Gold manufactured by the Parsec Group in Bel Air, Maryland. (Note: This product is now available as "Plate+" from Sprinco, USA the authorized distributor for shooter materials from Parsec. Any questions or comments should be directed to Sprinco not Parsec.) This product is a colloidal suspension of extremely finely divided (less than 0.5 microns) Molybdenum Disulfide, or "Moly", in a light oil with various proprietary inhibitors. According to Parsec/Sprinco, one could use the product to coat the inside of a gun barrel and increase the corrosion resistance of the barrel and not have to use Moly coated bullets to get the benefits of reduced galling or copper deposition. Being able to coat the barrel offered the chance to compare various combinations of bare and coated barrels and bare and coated bullets. I have a sporterized Model 1903 Springfield with the original military 30’06 barrel (well used) that had never had Moly coated bullets fired in it. Although not an accurate gun, it would work nicely for a set of velocity experiments. I cleaned the barrel thoroughly with a chemical copper remover (Barnes C-10) until there was no sign of copper and followed this with JB (a very, very mild abrasive) and finally a fine polishing compound used on plastics. I then loaded up 100 rounds using military brass, Remington 150-gr. soft points and H414 powder with a load that had worked well in the past. All 100 rounds were as alike as possible. Fifty of the bullets were Moly coated using the NECO tumbling process. The bullets were 0.065" from touching the lands in order to keep the overall length short enough to feed through the magazine. The experiment first consisted of firing 25 rounds of non-coated bullets through the clean barrel. As expected there was considerable evidence of copper in the bore. I again cleaned the barrel of all signs of copper using the above process. I then fired 25 rounds of Moly coated bullets. There was some copper on the lands following the firing, but not nearly as much as with the bare bullets. (Remember that this is a rough, used, military barrel. A modern, lapped barrel would probably show no copper.) Cleaning was easier and followed the above procedure until there was no copper. The barrel also had no apparent sign of Moly, as it appeared shiny like fresh steel. Following the Parsec/Sprinco instructions, I corked the barrel, filled it and soaked it in Spica Gold/Plate+ for 5 days (48 to 72 hours recommend) then cleaned with a few dry patches. I observed a dull gray coating on the bore. I then fired 25 rounds of bare bullets in the Moly coated barrel. I observed some copper fouling on the lands. I judge that it was about the same as that following the Moly coated bullet firing. I then ran a few patches through the barrel and made no attempt to clean it. The last test was with Moly coated bullets in the Moly coated barrel. Again there was some copper fouling, some of which was left over from the previous test. But I couldn’t see particularly more than before. The velocity (in feet per second and the group sizes are in inches) results were as follows:



BULLET
BARREL
HIGH
LOW
MEAN
SPREAD
STD. DEV
GROUP


Bare
Bare
2777
2719
2747
58
13
3.8"


Moly
Bare
2735
2665
2701
70
19
3.4"


Bare
Moly
2819
2773
2789
46
13
4.7"


Moly
Moly
2796
2726
2753
70
18
4.2"





Conclusion
Moly coated bullets do cause the velocity to drop as reported in the literature. A Moly coated barrel will give increased velocity as reported by the Parsec/Sprinco. A combination of the two cancel and give essentially the same results as no Moly at all. Note that the standard deviation for Moly coated bullets was over 45% greater than with bare bullets. I don’t understand why. There was no apparent effect on group size, but this is no benchrest gun either. How long will the coating on the barrel last? I don’t know. Parsec/Sprinco suggest running a patch with the Spica Gold/Plate+ through the barrel after each firing string, i.e. when you would normally clean it, and you should get 500 to 1000 rounds before a re-soak is needed. We will see. Frankly, coating the barrel seems to have some advantages: no fuss with Moly coated bullets, a slight gain in velocity, and a corrosion resistant coating in the barrel. I have done some reading of the scientific literature on Moly and there is repeated evidence that Molybdenum Disulfide plus water (in the air) plus oxygen (also in the air) will yield a bit of sulfuric acid which is not good on either your bullets or your barrel. I would like to see some more experimenting along the lines of the above. If you are interested in such experiments, contact Sprinco USA, Inc. in Chandler, Arizona at 800-397-9530 who now offers small amounts of Plate+ for the shooter.

[Echd]

That is an interesting article.

Moly coating used to be a big "thing" in high power shooting when I used to do it and it has mostly fallen by the wayside. I believe benchrest shooters nixed it quickly, although that was never my discipline. Reasons cited were generally mess and annoying application, it leaves a nasty residue in the barrel that is difficult to clean, and a hotly-debated-but-I'm-not-sure-if-it-was-ever-proven possibility that the residue could be corrosive in the barrel in high heat environments. Sprinco claims that plate+ is acid neutralized, as many stated that heat and the chemical remnants of a fired cartridge in the bore could combine with the moly and make sulfuric acid (this is one of the reasons people thought moly was the devil back in the day). Other people just thought it was plain old hygroscopic, and therefore made rust more likely.

I would personally like to see test results from someone who isn't trying to sell the stuff, but it also is a very old article (dated 1999) and I can't find any information other than passing references in very old forum posts to that coating system (just a colloidal suspension of the same stuff that goes on bullets). The only reason that I find it a bit questionable is maybe because of some of the rather outlandish claims made in http://www.sprinco.com/molycomparison.html . Especially the part where they claim that moly coating bullets costs over $700 for 1500 rounds. Moly was annoying and messy to apply, but it was never especially expensive. Or where it had "no apparent effect on group size", but the groups were 0.4 to 0.9 inches larger. Also because it also promises to smooth out and lighten your trigger pull, somehow modify the cyclic rate of automatic firearms, and also do your laundry.

Sprinco is still around and I have used their MG oil before. I found it to be good and serviceable stuff, but I am not a tribologist and Mobil 1 is generally good enough for my lubrication needs.

There is a similar product, MolyFusion oil by Shootersolutions. Unfortunately about the only info on it is from the early 2000s, and it's almost always a "Techshooter" posting / raving about it on a forum (he admits he is selling it). In 2008 a "rangerruck" pops up on several forums with the same posts about the product...


for those who do not know; the molyfusion is being updated by the inventor right now. The new formula should be ready by the end of the month.
For those who don't know, this is a fabulous product, and I highly suggest you get some. In a nutshell, it combines, COMBINES, with your bore metal, to become a diff metalurgically chemical bond alltogether. it makes your bore smoother, tighter, faster, easier to clean, and it does this foreever. I have rifles that I molyied 4 years ago, and they are still fantastic.
i side benefit, that is not claimed, yet many who have tried it will allude to;
it increases the accuracy of your rifles a bit. It is not said to be so by the mfgr, but most dudes who have used it, will tell you it does. i will tell you myself it does. If you have any other questions , check over on the sponsors at xxxxxxxxxxx.com, or look for i think it is called xxxxxxxxxxxxx.com
There is a nice pic of a world record group from a 17hmr over there; it will totally stun you at 100 yds...

It's like a Herter's catalog! Some of the claims are suspect or dubious, some are impossible enough that even the least scientifically minded should be able to discard. To their credit, they do claim that the product they are selling is not normal molybdenum sulfide and may be something else entirely. However, it appears to be a newer implementation of the same concept.

It would be interesting to test, but I find it very strange that there is no formal information out there on this, especially for something so old. Maybe because it is so old? The pragmatist in me wants to say that if this stuff did work as advertised with no downsides, it would be common practice, and not two old products dating to 1999 and the early 2000s. After all, who doesn't want free velocity with somehow no pressure increase (as per Sprinco's website and Techshooter)?

I do not want it to seem I am attacking the source, but there is a lack of third party verification here that didn't emerge from an unsigned Web1.0 page that looks like someone just ripped it off Netscape Navigator. It also flies in the face of much more verifiable information from less biased, or at least more well known and larger sources.

Regardless,taken at face value, the claim is that the various moly oil treatments bond with the barrel and enter the substrate and whatnot, making the first few microns contacting a bullet a different surface than what is ordinarily contacted (they seem to distance themselves from the word "lubricant" in favor of "treatment"). Sprinco themselves even state at that point that using moly bullets with what is presumably the same load in a treated bore gives reduced velocity. Which either implies there is a point where you can increase slipperiness and gain velocity and somehow this oil just so happens to hit it and is useful for all firearms (again, in defiance of all we know, have discussed, and observed here), or that something else is at play.

[M-Tecs]

I started with Moly mostly due to a quest for longer usable accuracy. Tried Danzac for a short time and I now use Hex Boron for all jacketed rifle bullets. None of the mess of moly and the benefits are well worth the efforts.

I never claimed to understand the why but per my chrono I also have to increase my powder charge to maintain equal velocity with the only variable being Moly, Danzac or Hex Boron bullet coatings verse bare. I have never tested or Chrono'd the bore treatment products so no comment.

[Echd]

Never tried Danzac. I have used DTACs which use some flavor of HBN, I think. It seems to do what moly promised without the downsides.

For the PSR game or metal targets, friction-reducing coated bullets are pretty much an all around win, as you are almost always velocity restricted anyway in competition. When shooting a high BC 6mm / 243 or 6.5 it's no problem getting that bullet to 1k plus anyways.

[noisewaterphd]

I like hBN for long range competition and I put it in my lubes.

Mainly because it helps put cold bore shots in the group, and with any luck increases my bore life. I tend to gravitate to overbores, so any little bit has to help, right? ;)

I never got into moly that much. At least beyond testing some factory coated bullets.

[M-Tecs]

When Kevin Thomas was with Sierra Bullets he tested the barrel life claims and found no difference for Moly. While not scientific my bore scope and accuracy testing do indicate that both Moly and HBN do give increased barrel life.

I also find better cold bore point of impact. For me the real benefit is accuracy doesn't fail of as quickly as the shot count increases.

[Lloyd Smale]

again kind of shows this is a non issue in the real world. thanks firefly
Lloyd I have fired some Lyman 45 bullets i coated and lubed,coated and sized and sized and lubed normally same alloy from my 45 acp all loads were 5 grains red dot CCI large pistol primer velocities were the same within reason the same happened when the cast coated bullets were swaged same velocity a bit better accuracy and less losses from scrapping coating off.
* On a side note cases with small pistol primers same coated sized bullets 5 grains Red Dot ran 30 fps slower and had a much wider standard deviation and poorer accuracy.

[Lloyd Smale]

Interesting no doubt. But this isn't the same stuff were using if I'm correct and even so a difference in 50 fps in a rifle at 2800fps is a very small change. What I found head scratching here was that Standard deviation was greater with the coated bullets but accuracy is better. That doesn't fly with standard reasoning. But then looking at it that small of a change is probably a non issue just like the small difference in velocity. Still looks to me like all this stuff is better ammo for argument then it actually effects actual ammo. thanks though mec-tec for at least posting some real world data
Interesting test here http://www.sprinco.com/testresults.html

Velocity Change With Moly Coated Bullets Vs Moly Weapons Oil
By: Dick Hatfield

Recently I became aware of a product called Spica Gold manufactured by the Parsec Group in Bel Air, Maryland. (Note: This product is now available as "Plate+" from Sprinco, USA the authorized distributor for shooter materials from Parsec. Any questions or comments should be directed to Sprinco not Parsec.) This product is a colloidal suspension of extremely finely divided (less than 0.5 microns) Molybdenum Disulfide, or "Moly", in a light oil with various proprietary inhibitors. According to Parsec/Sprinco, one could use the product to coat the inside of a gun barrel and increase the corrosion resistance of the barrel and not have to use Moly coated bullets to get the benefits of reduced galling or copper deposition. Being able to coat the barrel offered the chance to compare various combinations of bare and coated barrels and bare and coated bullets. I have a sporterized Model 1903 Springfield with the original military 30’06 barrel (well used) that had never had Moly coated bullets fired in it. Although not an accurate gun, it would work nicely for a set of velocity experiments. I cleaned the barrel thoroughly with a chemical copper remover (Barnes C-10) until there was no sign of copper and followed this with JB (a very, very mild abrasive) and finally a fine polishing compound used on plastics. I then loaded up 100 rounds using military brass, Remington 150-gr. soft points and H414 powder with a load that had worked well in the past. All 100 rounds were as alike as possible. Fifty of the bullets were Moly coated using the NECO tumbling process. The bullets were 0.065" from touching the lands in order to keep the overall length short enough to feed through the magazine. The experiment first consisted of firing 25 rounds of non-coated bullets through the clean barrel. As expected there was considerable evidence of copper in the bore. I again cleaned the barrel of all signs of copper using the above process. I then fired 25 rounds of Moly coated bullets. There was some copper on the lands following the firing, but not nearly as much as with the bare bullets. (Remember that this is a rough, used, military barrel. A modern, lapped barrel would probably show no copper.) Cleaning was easier and followed the above procedure until there was no copper. The barrel also had no apparent sign of Moly, as it appeared shiny like fresh steel. Following the Parsec/Sprinco instructions, I corked the barrel, filled it and soaked it in Spica Gold/Plate+ for 5 days (48 to 72 hours recommend) then cleaned with a few dry patches. I observed a dull gray coating on the bore. I then fired 25 rounds of bare bullets in the Moly coated barrel. I observed some copper fouling on the lands. I judge that it was about the same as that following the Moly coated bullet firing. I then ran a few patches through the barrel and made no attempt to clean it. The last test was with Moly coated bullets in the Moly coated barrel. Again there was some copper fouling, some of which was left over from the previous test. But I couldn’t see particularly more than before. The velocity (in feet per second and the group sizes are in inches) results were as follows:




BULLET

BARREL

HIGH

LOW

MEAN

SPREAD

STD. DEV

GROUP



Bare

Bare

2777

2719

2747

58

13

3.8"



Moly

Bare

2735

2665

2701

70

19

3.4"



Bare

Moly

2819

2773

2789

46

13

4.7"



Moly

Moly

2796

2726

2753

70

18

4.2"





Conclusion
Moly coated bullets do cause the velocity to drop as reported in the literature. A Moly coated barrel will give increased velocity as reported by the Parsec/Sprinco. A combination of the two cancel and give essentially the same results as no Moly at all. Note that the standard deviation for Moly coated bullets was over 45% greater than with bare bullets. I don’t understand why. There was no apparent effect on group size, but this is no benchrest gun either. How long will the coating on the barrel last? I don’t know. Parsec/Sprinco suggest running a patch with the Spica Gold/Plate+ through the barrel after each firing string, i.e. when you would normally clean it, and you should get 500 to 1000 rounds before a re-soak is needed. We will see. Frankly, coating the barrel seems to have some advantages: no fuss with Moly coated bullets, a slight gain in velocity, and a corrosion resistant coating in the barrel. I have done some reading of the scientific literature on Moly and there is repeated evidence that Molybdenum Disulfide plus water (in the air) plus oxygen (also in the air) will yield a bit of sulfuric acid which is not good on either your bullets or your barrel. I would like to see some more experimenting along the lines of the above. If you are interested in such experiments, contact Sprinco USA, Inc. in Chandler, Arizona at 800-397-9530 who now offers small amounts of Plate+ for the shooter.

[Lloyd Smale]

Jim I just don't shoot cast .30s anymore. I fooled with them about 20 years ago and had some a couple bad experiences on deer and quit. For the most part I'm a handgun and lever gun caster. I will though try to at some time this summer set up the chrono and test the 50 beo or maybe my 356 big bore with both coated and lubesized bullets and see what happens.
The differences we're talking about are small, I'm not surprised that they are less than the normally observed variations seen from a pistol or revolver. I'm pretty confident that they would be detectable from a long-range bolt gun either as a reduction in velocity or a change in the poi. Would really like it if Lloyd would volunteer to do the test using commercial or cast .308 that are identical other than coatings. I'd chip in.

At the risk of going off topic, I sort 45acp brass by primer size and only load the large, small is kept in case of future shortages of brass or LPP.

[noisewaterphd]

I suppose it depends on how meticulous you want to be, and what your end goal is.

50fps is a huge deal to me, and probably any long range shooter.

I also run lots of mags right up to and past redline. In this case, any increase in pressure is important, making it essential to understand the consequences of changing bullet coatings, etc..

Nobody ever tried to convince you that you should care, so if you don't, then that is fine. We only tried to show you that your previous understanding was backwards.


What is more important here is for anyone reading the thread that doesn't understand any of this yet to walk away with an accurate understanding of how changes in the friction of their bullet can and will effect the pressures and velocities of their handloads.

We do not want the worst case scenario of someone new to the hobby thinking that powder coat is going to decrease their pressures and ending up hurt as a result.

Even at the low pressures and slow velocities in something like the 45 acp, if you have good handloading practices, and a quality chronograph you will see that even changing from lube to PC has a consistently measurable and meaningful effect on both.

This absolutely can not be written of as margin of error. That would be irresponsible.

[M-Tecs]

I suppose it depends on how meticulous you want to be, and what your end goal is.

50fps is a huge deal to me, and probably any long range shooter.



When you are trying to hold 1/4" elevation at 1,000 yard 50 fps is huge to me also.

[Lloyd Smale]

I cant ever remember having to worry about 1/4 elevation at a 1000 yards with any cast bullet gun. 1000 yard shooting has so much drop that its a game of knowing your load, trajectory and having an accurate load. 50fps just means learning a different trajectory curve. Guys shoot 308s at a 1000 yards and wont give them up for a 300 mag that's 400fps faster. but then I guess if it does matter to you it does.

[M-Tecs]

50 fps standard deviation in a specific load at 1,000 yards will give you elevation issues. 50 fps doesn't show at 200 yard but it becomes very apparent at a 1,000.

With a Sierra 30 175 MatchKing moving at 2600 verses 2650 you get 18 inches more drop at a 1,000 yard or 1.8 moa. To be competitive in F class or bench you need to hold 1/2" or better for elevation (5 inches at a 1,000 yards). For position matches you need 1 MOA or better to be competitive. While I do shoot BPCR at a 1,000 I am not serious enough about it to comment on what is and isn't competitive other that knowing I am not.

[Lloyd Smale]

yup and the difference is a couple more clicks on your elevation turrent if you know your gun. Its why accurate 308s still compete in 1000 yards shooting next to flatter shooting guns. Using 175s I would guess you have a bigger problem in them going subsonic before a 1000 yards then anything. Kind of why the 308 guys tend to go with 155s. At least that's what I'm told by guys who do it. Personally I worry about a max of 600 yards because that's a far. Were getting a bit off topic here so ill say good by to this one.
50 fps standard deviation in a specific load at 1,000 yards will give you elevation issues. 50 fps doesn't show at 200 yard but it becomes very apparent at a 1,000.
With a Sierra 30 175 MatchKing moving at 2600 verses 2650 you get 18 inches more drop at a 1,000 yard or 1.8 moa. To be competitive in F class or bench you need to hold 1/2" or better for elevation (5 inches at a 1,000 yards). For position matches you need 1 MOA or better to be competitive. While I do shoot BPCR at a 1,000 I am not serious enough about it to comment on what is and isn't competitive other that knowing I am not.

[M-Tecs]

Getting off topic is one issue but the real issue is we are not talking about the same thing. You claim that bullet coatings increase velocity, however, you have been unable to provide in documented instance were this is the case.

I do not have the knowledge or experience to comment on any coatings other that Moly, Danzac and HBN on jacketed bullets in rifles chambered in .223, 22-250AI, 220 Swift, 6mm XC, 240 NM, 243 Win, 260 Rem, 6.5 x 284, 308 and 300 Win, Mag. In every case the MV was lower for coated bullet verse non coated bullets with the variable being the coated bullets. Same for everyone else's experience and data. You are initialed to your opinion but it contradicted everyone's experience and data.

Under three hundred yard loads with surprisingly high SD's group very well, these same loads will not cut it at long range due to the lack of ability to hold elevation due to the high SD's.

The current king of the hill bullet for 1,000 competition in 308's is the Berger 185 grain Juggernaut.http://buybergerbullets.3dcartstores.com/30-Cal-185-Gr-Juggernaut-Target_p_69.html

The 155 was the max weight allowed for Palma matches at one time. The only time 155 are preferred is when the rule don't allow for heavier or you are shooting a shorter barreled rifle that can't keep heavier bullets super sonic at 1,000.

As pointed out earlier a 50 FPS SD will give you a 18 inch POI difference. This is not acceptable or competitive thus the large amount of data collected to develop long range loads. Lots of data collected none of switch supports your claim of high velocity with coatings.

Now you are arguing about issues no one broached. I don't believe it's due a lack of understanding on your part but it's just a desire to argue.


yup and the difference is a couple more clicks on your elevation turrent if you know your gun.

Maybe all those years of Long Range competition were a waste and I failed to learn how to predict MV. Please tell me how to do this? When I am shooting my 308 Palma rifle with a load that has a SD of 50 FPS per your claim of "know your gun" how do I predict what the MV with be so I can adjust of the SD of 50 FPS?????

[Lloyd Smale]

I was told that a 308 wont keep a 175 super sonic at a 1000 yards. Is that wrong? I'm not a 1000 yard shooter and was just passing on what I was told. Is it so close that that 50 fps would make it subsonic and fly funny so that that 50 fps couldn't be compensated for with just a few clicks of the elevation turret. I'm here to learn if you have actual experience. As to coatings increasing or decreasing velocity I think its been showed here that for 99 percent of us the difference is a non issue that is less then the difference of that two identical rifles in the same caliber can show with the same load. I do agree with you that it doesn't take much to get decent accuracy at 300 yards. Even my experience which is limited to 600 yards shows that MANY loads at 300 fail miserably at 600 so I'm sure its really amplified at a 1000.

[M-Tecs]

I was told that a 308 wont keep a 175 super sonic at a 1000 yards. Is that wrong? .

Yes that is incorrect. The 173 FMJ M118 Special ball, M118LR and Federal Match with 175 grain matchkings don't have a problem staying supersonic at a 1,000 in the M-14 with a 20 inch barrel.

M852 or Federal Match ammo with 168's out of 20" M14 will not stay supersonic at a 1,000. With longer Match rifle barrels you can push the 168's hard enough to stay supersonic at a 1,000. The Sierra 168 bullet was developed for 300 meter International shooting.

[Lloyd Smale]

beauty of this place. Even after all these years I still can learn things on here.
Yes that is incorrect. The 173 FMJ M118 Special ball, M118LR and Federal Match with 175 grain matchkings don't have a problem staying supersonic at a 1,000 in the M-14 with a 20 inch barrel.

M852 or Federal Match ammo with 168's out of 20" M14 will not stay supersonic at a 1,000. With longer Match rifle barrels you can push the 168's hard enough to stay supersonic at a 1,000. The Sierra 168 bullet was developed for 300 meter International shooting.