I have a new article on Brinell hardness....

[Harry O]

and what it means to the bullet caster.

http://www.sixshootercommunity.com/harro/4-brinellhardnessandbulletcasters.html

[bigdog454]

Great article!

[felix]

Excellent, Harry! ... felix

[theperfessor]

Very good article well worth reading. Thanks for posting link.

[Charlie Two Tracks]

Got it saved to the computer.

[Marlin Junky]

Well heck, since I'm applying an annealed gas check to most of my boolits, I'm going right up to the BHN*1422 value determined from my 100% reliable :-( QuickLoad! If that doesn't work then I'm practically guaranteed a non-annealed gas check will solve all my problems. [smilie=l:

But seriously, thank you for posting that interesting article. I have been wondering how the 1422 was derived... and I've been using 1440 all this time. Now I finally know what's been ailing my '06!

In all reality though, isn't the pressure data published by Lyman more reliable than that generated by QuickLoad? I can't cite exact discrepancies off the top of my head, but I sure seem to recall some disagreement between Lyman and QuickLoad.

MJ

[Marlin Junky]

I've got another issue with respect to this hardness thing in rifles: How does one know if their boolits are too hard? Is it by looking at the fouling near the muzzle, perhaps caused by too much friction? Let's assume we're shooting boolits .002" over groove and obturation or lack thereof doesn't apply.

MJ

[Harry O]

I use the 1,422 number for plain base bullets. I have not done any extensive tests on gas checks, but it seems that going about (and I stress the ABOUT) 1-1/2 times that number (or roughly 2,100) is pretty close to the upper limit for gas checks.

Rough number, I use plain base up to about 22,000psi. Above that, it is not worth making it hard enough for plain base. I use gas checks with up to about 32,000psi. Above that, I use jacketed.

I do not have one mix. I match the hardness of the mix to match the pressure. That means that a 5gr load of Trail Boss in a 38-40 CAS load is just about as soft as I can make it. A .38 Special +P load will be about Bhn 15-16. With gas check, I start soft lead again, but by the time I get to the top, I am back up to about Bhn 15-16.

I figure the hardness of the mix before doing any casting, by using formulas in a different article. It is:

http://www.sixshootercommunity.com/harro/7-castbullethardnesscompletingcircle.html

I wish I had better ways to get the pressure of a load. I do not have a computer program. A friend of mine had one that we played around with once and it came up with some strange results. For example I got a number of cheap Winchester White-Box 9mm factory loads that were loaded out to maximum OAL. They were just a little too long for my Browning P-35. I put them in a loading press and shortened them to what the OAL length was given for handloading. From memory, it was about 1/32" shorter. The computer program showed that shortening it upped the pressure to proof load levels. They shot great, though.

I do have a Powley Computer that I have great faith in. I used it before there were cheap chronographs available. After I got my first chrono, I was very pleased to find that the Powley was VERY accurate, at least when it came to velocity. It also figures pressure and because of the velocity results, I trust it. Of course, that is only for rifle loads with IMR powders.

I have a few loadbooks that list pressure and I go by those, with nothing else to go on. So far, so good.

[Bret4207]

Okay, maybe I'm dense, but this sentence is bothering me, "Remember that as long as the load applied is in the elastic range, the bullet will return to its original size and shape after the load is removed (ie, as the bullet leaves the barrel)." Are you saying that any common lead alloy in use for cast boolit shooting will travel down the barrel and return to it's form from beofe it traveled the barrel? I have never see anything like this. Anytime any change is made to any of my lead alloys it always results in the change remaining. This sounds like you're describing spring steel. So, I'm confused.

Also, we can have three different alloys giving the same Bhn reading that react in 3 different manners to a given load or 1 alloy treated 3 different ways that shows 3 different Bhn readings and reactions. I think the makeup and treatment of the alloy has just as much to do with our accuracy and success as sheer Bhn readings.

[Marlin Junky]

Okay, maybe I'm dense, but this sentence is bothering me, "Remember that as long as the load applied is in the elastic range, the bullet will return to its original size and shape after the load is removed (ie, as the bullet leaves the barrel)." Are you saying that any common lead alloy in use for cast boolit shooting will travel down the barrel and return to it's form from beofe it traveled the barrel? I have never see anything like this. Anytime any change is made to any of my lead alloys it always results in the change remaining. This sounds like you're describing spring steel. So, I'm confused.

The difference in dimensions between the boolit alloy under load and not under load, while still in the elastic range, would probably be imperceptible to the handloaders' caliper.


Also, we can have three different alloys giving the same Bhn reading that react in 3 different manners to a given load or 1 alloy treated 3 different ways that shows 3 different Bhn readings and reactions. I think the makeup and treatment of the alloy has just as much to do with our accuracy and success as sheer Bhn readings.

You're going to need to explain that one with some examples; however, your suspicion, "I think the makeup and treatment of the alloy has just as much to do with our accuracy and success as sheer Bhn readings", may be correct for other reasons; e.g., coefficient of friction or malleability, perhaps.

MJ

[Echo]

Great article, Harry O. Printed & saved in my Big Book.

Bret, remember we are talking about the base of the boolit. Sure, the rifling is impressed on the sides, but the pressure there HAS to be greater than the pressure on the base (because it HAS changed and didn't go back to the way it was).

[Marlin Junky]

Bret, remember we are talking about the base of the boolit. Sure, the rifling is impressed on the sides, but the pressure there HAS to be greater than the pressure on the base (because it HAS changed and didn't go back to the way it was).

The forces on a base are compressive, those that form the rifling are shear... two different animals.

MJ

[Bret4207]

You're going to need to explain that one with some examples; however, your suspicion, "I think the makeup and treatment of the alloy has just as much to do with our accuracy and success as sheer Bhn readings", may be correct for other reasons; e.g., coefficient of friction or malleability, perhaps.

MJ

Okay- We can take 3 different lead alloy samples- say aged straight WW, 10-1, and fresh, juiced WW with more Sn/Sb. All 3 can be around 11-12 Bhn. All 3 will react differently to sizing, launch and impact with the same powder load. We can also take 1 alloy, say juiced WW, treat it 3 different ways and get 3 different Bhn readings. It will react differently as above.

IOW- Bhn alone isn't the whole story. Bhn alone = HARDCAST is mo' bedder!!!, which as we all should know by now isn't true. I find the concentration on Bhn used solely as the determining factor in what a given alloy will do with a given pressure to be inaccurate based on my experience.

[Harry O]

Marlin Junky has answered the questions as well (or better) than I could. As far as the different makeup for three mixes that have the same Brinell, that may be somewhat true during casting. However, for normal types of lead/tin/antimony mixes used by handloaders, I have not found any significant difference in how it acts in the barrel.

However, the difference in makeup makes a major difference in how well it casts. For example, a Bhn 11-12 mix (from your example) with strictly pure lead plus antimony will be difficult to cast if the bullet is very complicated at all (such as a hollow-base bullet). Pure lead plus enough tin to bring it up to Bhn 11-12 would cast like a dream. However, from my experience there is no major difference with how well the two handle an equal amount of pressure in the same gun.

I have also have taken ONE mix and cast it and quenched it in different ways. When air-dropped, a 100gr bullet had the highest Bhn. The 200gr bullet was approx 3/4 to 1 Bhn softer. A 350gr bullet was approx 1 Bhn even softer. Even though the mix was EXACTLY the same, the difference was because how quickly the the bullets cooled -- the heavier the bullet, the longer it took to cool. The same test mix and bullets dropped into cold water directly from the mould gave Bhn's that were pretty close to equal and approx 50% more than the air-dropped ones.

They all behaved during shooting exactly how I would have expected by the Bhn each had even though the mix was exactly the same.

[Bret4207]

Your experience doesn't match up with mine. I have seen the make up of the alloy effect both accuracy and reaction to the pressure with similar Bhn, but different makeup. I don't have the technical training to put my observations into words beyond saying IME it does happen.

[Bass Ackward]

I wish I had better ways to get the pressure of a load. I do not have a computer program.


Great article on the metal part Harry.

The main message is that is simpler / easier if you stay elastic. Especially if you use just a surface lube. Surface lubes work when the bullet design can support itself. But it ain't just pressure Harry. More factors enter the equation that I can't explain.

I just know that if I work under the right conditions, the strongest part of my bullet should be the lube. Supported by hydraulic forces and steel, I can establish "mold like" conditions to control the plastic state. (The real question is, if I control movement, is the plastic state ever reached?)

If I can pull this off, and if the gun can maintain those conditions (seals and doesn't build fouling) I can operate in the plastic zone. Especially if I have a GC where the force is the highest requiring the most lube and I balance antimony and tin. I think that this is why you can actually shoot better at times when you do foul because the lead can then be smoothed by the next slug and seal where the clean barrel could / did not.

If I can't establish and maintain this during the plastic period, or if the bullet design won't allow me, (must have grease grooves that are deeper than the rifling to allow 360 equalization of hydraulic force) then I need a harder bullet or to cut pressure to get back to non-deformity. That is why choking is favored by many. The lube is the first thing to go without seal and it leaves from the area where it is needed most. (the base)

I find that it's when you enter the plastic state that your mix becomes important. And this is where I become the most ignorant. The higher the antimony that you have free (more than tin content) the more problems that are encountered. And it seems that you are better with lower amounts period.

That seems to be why the old lead tin mixes were preferred when they knew they were going plastic and why guys seem to do well with 50/50 WW and pure. It could be as simple as going back to fouling that does not build and seals. But again, no rules.

[357shooter]

Sorry to be a lone voice of disagreement, however:

My test results are very different. I only load for 357/38 revolvers with the primary objective of accuracy. After testing a few thousand boolits the most accurate alloy is pure lead with a 10inch strip of solder for every 10 lbs, with a 5.1 load of 700X. That's roughly 30,000PSI with the 168 grain Keith boolit and roughly BHN 7 (or so). Very close to that is 4.9 grains of HP-38 which is 27-28,000PSI.

Each time alloy BHN was increased the groups opened up, each time I lightened the load (less pressure) the groups opened, each time I used a different powder the groups opened.

If the boolit design doesn't work in the gun (nose to throat in my case) maybe these calculations can be helpful. However my test results say they flat don't work. At least in my 357 revolver, matching the alloy to the pressure doesn't help accuracy at all.

Rifles, that's a whole nother discussion that I can't comment on as I have no idea. Matching pressure to the alloy may matter.

[Harry O]

I wish everyone who posts to this website would get the book by Veral Smith, Jacketed Performance with Cast Bullets (from memory). Where the Lyman books are a great start, the Smith book is an advanced degree in casting.

Naturally, one of the reasons I like it because Veral Smith believes in the 1422 number (as does Richard Lee and several others). Veral Smith also can go over that number at will. He is one of the very few people who has the experience and knowledge to do so. For beginners, or for people who don't want to waste their time trying to find the magic combination of factors to exceed the 1422 limit, this is the quick and easy way to get accuracy. As Bass Ackward said, "The main message is that is simpler / easier if you stay elastic." That is EXACTLY what I am saying.

As far as those who do not have the same experience as I did, so be it. I am not going to call you names. I have done specific experiments, varying one item at a time to find out what they individually do. These experiments agree with my engineering training. Going over the yield point never does good things to a bullet.

Just a couple of comments. Mr Smiths book has a GREAT picture of an experiment he did. He made a mould for a bullet that was bore diameter. At both ends, he created a belt that was a little over groove diameter, to seal it. Then he cast a bunch up with pure lead and shot them with increasing amounts of powder. The rear deformed. The higher the load, the more deformed it was, working from the rear towards the front. The bullets were put side by side and photographed. You could easily see the progression with increasing pressure. Of course, the bullet was not accurate. It was done to prove that deformation starts at the rear of the bullet and works forward if the bullet is not hard enough. It was pretty eye opening to me.

Another thing is about the "old guys" who used 10:1 lead/tin mixes at higher pressures than this formula indicated. That is true, but if you go back and carefully read Keiths book, Sixguns, he says several places that there was some leading with that combination. As long as he could get decent accuracy, scrubbing the leading out was a necessary evil. I would say that Keith was another who could exceed the 1,422 limit, but I am not sure that it was at will. From those books, it was obvious that he was always experimenting to find a combination that would work for him. When he found it, he stayed with it.

Bass Ackward: I have experimented with VERY hard cast bullets (up to Bhn 37-39). The first experiment was with straight monotype, dropped from the mould into cold water. The mix was approx 17.5% antimony, 9.5% tin and the rest lead. The bullet was so brittle that crimping the case into the crimping groove cracked the bullet. There was entirely too much free (unalloyed) antimony in the mix. The lead could only take about 6% of the antimony in alloy and the rest (approx 12% more) was between the lead crystals.

I increased the amount of tin to match the amount of antimony. The end mix was approx 15% antimony, 15% tin, and the rest lead. The excess antimony alloyed with the tin and the end result was a tough bullet that would take a full pressure load (approx 45,000psi and nearly 2,200fps). With a Bhn 15-16 mix (in the same bullet and same gun), the accuracy went bad at about 1,400fps and visible leading started about 200fps higher. I believe I put in a little more tin than was absolutely necessary to soak up the rest of the antimony, but I was in a hurry. I may go back and refine the mix later.

I have not done as much experimenting with lube. From the limited experience I have, I think it is hard to increase the maximum limit by very much by only changing lube. However, a bad lube will reduce the limit by quite a bit. Several lubes that I made were bad lubes. I have settled on commercial NRA 50-50 lube for higher pressure loads. It seems to work for me.

[32ideal]

HARRY O have you performed any tests using plastic wads (PVC, LDPE, HDPE, Plastic milk cartons ETC) on the base with plain base bullets?
32ideal

[Harry O]

31 Ideal: No I have not. I use commercially available fiber wads between the powder and the bullet with BP loads. It does seem to help them a bit. I have not tried them with smokeless loads because the smokeless powder does not completely fill the case to the bottom of the bullet and hold the wad in place. I would not want it to fall down and then get propelled against the bottom of the bullet when the powder ignites. Who knows what would happen.

[C.F.Plinker]

If you are operating in the elastic region - pressures below 1422 times BHN - how much obturation can you get? For example, if your boolet diameter is 0.0005 below groove diameter will it obturate enough to seal the bore and prevent gas cutting? I can see where this would probably occur in the plastic region - pressures greater than 1422 times BHN - because you have enough pressure to deform the boolet permanently.

If you are in the elastic region how do you know if the alloy is strong enough to resist the forces acting in shear that are causing the rifling to spin the bullet? How does this relate to twist? Could a boolet that works in a Marlin 44 Mag with a 38" twist not have enough strength and strip the rifling or get gas cutting in a revolver with a 20" twist?

[Bret4207]

I'm going to reread what has been written here several times and see if I can put my observations into understandable words.

[Marlin Junky]

Bhn alone isn't the whole story.

Heck no, not to the accuracy equation; however, BHN* defines the boundary between elastic and plastic "states" pretty well. If BHN were the only variable, all this would be pretty easy but we really don't have (at least to my knowledge) a good way of measuring boolit coefficient of friction which would be dependent on alloy composition (e.g., ratio of Sb to Pb) and consistency. Boolit coefficient of friction would also be very dependent on BHN and chamber pressure (not to mention boolit lube) which would make things even more interesting, perhaps confusing to some and satisfyingly quantifiable 8-) to others.

MJ

* Note: BHNx1422, that is.

[BCB]

I printed the article to read a time or three as I can’t read articles that are lengthy on my computer. The screen is too small…

One thing that I really was glad to see was the fact the wheel weights aren’t the 10-12 now as they were years ago. I was thinking my SAECO tester was not so good. I continually get what Harry O indicates—7-9 most of the time. Now that’s not good as the older alloy would have been better I suppose, but it did verify my tester was O.K….

Good article…

BCB

[Gohon]

Doesn't mean anything except your tester is showing 7-9. Last batch of WW I smelted down was gathered about March of this year and my Lee tester read 11-12 but I do separate the stick on from the clip on type. I don't think any of the testers sold to the general public are all that accurate anyway if measured against lab equipment. Whats important to me is they are consistent.

Truth is I don't pay much attention to that stuff anyway. All I know is I'm running a gas checked 190 grain out of a 357 maxi at 2,100 fps and get no leading with great accuracy. I've pushed a 160 grain bevel base from the same gun at 1,600 fps with the same results. I haven't a clue what the pressure of those loads are.

[BCB]

Doesn't mean anything except your tester is showing 7-9.

Well, I disagree with that statement, but that is not the subject of this topic. Harry O certainly indicates that BHN us inportant...

I have never gotten 11-12 on any wheel weights with my SAECO. But I have gotten the 15+ with a know alloy of Lyman #2. To me that confires the SAECO is correct or at least would indicated it is accurate. Don't know anything about the Lee tester, but from what I have read about them, it may be a visual subjective (somewhat) decision as to what the actual BHN is. SAECO has lines that can be aligned and read...

BCB

[Gohon]

I'm aware of what the topic is about and I didn't mean to get it off track but you brought it up. On the other hand if one accepts what this thread is about then one has to know what the bhn is now don't they.

Go over to Lasc.us and there is a write up on BHN testers using Cabin Tree, Saeko and the Lee tester. About a dozen different individuals were selected with equal numbers of the different testers to test samples of a known BHN. Not a one of the individuals were consistent with others in the group. Some were off as much as 4 points of the known BHN. Only one of the three testers was consistent and close to the known sample.

That was my point......if what you use is consistent across the board then if doesn't matter if what you are using is not spot on.

[BCB]

Gohon,

I thoroughly perceive the demeanor of your response. And I completely understand your opinion and well expressed facts. And you have stated it a civil way that is truly not debatable, at least not by me…

‘Nuff discussed between you and me…

BCB

[Harry O]

If you are operating in the elastic region - pressures below 1422 times BHN - how much obturation can you get? ....

If you are in the elastic region how do you know if the alloy is strong enough to resist the forces acting in shear that are causing the rifling to spin the bullet? How does this relate to twist?

The slope of the stress strain "curve" in the elastic area is straight. The slope is called the Modulus of Elasticity. It is 2,000,000psi for lead. You can use this to calculate how much the bullet will shorten and then use that to calculate the obturation you will have -- but only up to the yield point. Beyond that, you cannot calculate anything with any accuracy.

Anyway, lets say you have a Bhn 15 mix and are shooting a 20,000psi .38 Special load (midway into the +P region). That is below the yield point so we can divide the pressure by the modulus. That is 20,000 / 2,000,000 = 0.010. This means that you take the original length of the bullet (front to rear) and multiply it by this number to get the length that the bullet will shorten. Lets say that the bullet is 0.700" long (a plain-base .38 Special semi-wadcutter). That means that under 20,000psi, the bullet will shorten by 0.70" x 0.010 = 0.007". It will be 0.693" long while under pressure.

That is change in length. How do we get the change in diameter? The change in length under loading is directly related to the change in diameter (90 degrees from the length) by a property known as Poisson's ratio. For lead, that is 0.431. (each metal has a different conversion number) That means that the change in diameter under 20,000psi of pressure is 0.007" x 0.431 = 0.003". That is more than enough to seal any leaks. I doubt that you could have a bullet 0.003" under, though. I have had no luck with undersized lead bullets. The pressure would escape between the wall and the underside bullet which would reduce the pressure and cause leading to boot.



The compressive yield strength of any metal is completely different from the shear strength for the same metal. Shear strength is always less than yield strength, but the exact percentage varies with each metal. In theory, the shear strength should be approx. 57% of the yield strength, but some metals are higher and some are lower depending on their atomic structure.

With lead, there is the same problem I mentioned about the yield strength. It varies all over the map depending on how the test was done. In any case, YES, the lead can strip out while trying to grip the rifling. Again, Veral Smith has some photos of this happening in his book. When this happens, the sides of the rifling are NOT parallel. There is a wider gap between the sides of the groove at one end than at the other. With shorter (or tighter) twist, there is a higher probability that the bullet will strip.

It would be possible calculate the the area of the side of the rifling times the number of grooves times the engraved length of the bullet and multiply it by the shear strength. That would be the maximum load that the bullet could take. The rotation of the bullet (which is the function of the twist and the speed) can be used to figure the force exerted. I have never actually done it and my guess is that the variables would make it pretty much impossible to get a very accurate figure. In most cases, however, if you stay below the yield strength, you should not have any problems with the bullet stripping out. With a VERY short twist (such as a full power load with a 160gr 6,5x54 Mannlicher-Schoenauer bullet in a barrel with one turn in 7.87"), that may not be the case, however. Sorry I cannot be more specific on how to calculate that.

[Harry O]

Doesn't mean anything except your tester is showing 7-9.

That is why the industrial testers I had a work had specific plates (very high priced plates I might add) that were a known hardness and they were used to periodically check the accuracy of the testing machine. I have not seen that done for ones being sold to bullet casters.

What I did for my private testers was take a stick of "pure" plumbers lead and I check my instrument against it from time to time. I still have a lot of room to run more tests on it. I have not had my testers change from one time to another using the same piece of lead. I have had 4 different hardness testers and still have three of them (I traded the SAECO one for a set of 41 Long Colt dies).

The WW's when I started casting about 20 years ago were definitely harder. The ones I get now are less hard. It means I have to add more monotype and tin to get the hardness I want. I just got about 150lbs of truck weights, though, and they are much harder (Bhn 11-12) than the most recent car WW's. They are so huge, that I have no doubt they need more antimony to keep them from flexing until they break.

[Ridgerunner665]

That article mentioned 18 wheeler WW"s...

I'm a truck driver and I have a few big truck WW's...he's right, they make those 1/2 ounce car weights seem microscopic, and the truck WW's are harder...I don't have a BHN tester yet, but i can tell that by squeezing them with pliers.

An 8 ounce truck WW...
http://i217.photobucket.com/albums/cc137/Ridgerunner665/1011101916a.jpg

Not many places have truck WW's though...most drivers and companies have gone over to using the CentraMatic wheel balancers
( http://www.centramatic.com/Home.aspx )

[Bret4207]

Anyway, lets say you have a Bhn 15 mix and are shooting a 20,000psi .38 Special load (midway into the +P region). That is below the yield point so we can divide the pressure by the modulus. That is 20,000 / 2,000,000 = 0.010. This means that you take the original length of the bullet (front to rear) and multiply it by this number to get the length that the bullet will shorten. Lets say that the bullet is 0.700" long (a plain-base .38 Special semi-wadcutter). That means that under 20,000psi, the bullet will shorten by 0.70" x 0.010 = 0.007". It will be 0.693" long while under pressure.



Doesn't that make the assumption that the entire boolit obturates? Again, in my experience, that doesn't always happen. And wouldn't the design of the boolit play into that? A bore rider with less bearing surface might start moving easier than a full body boolit and have less time for the pressure to affect it?

[Harry O]

Doesn't that make the assumption that the entire boolit obturates? Again, in my experience, that doesn't always happen. And wouldn't the design of the boolit play into that? A bore rider with less bearing surface might start moving easier than a full body boolit and have less time for the pressure to affect it?

You are correct that the bullet does not act uniform from front to rear at the same instant. The numbers I used are an average. The effect will be greater where the pressure is applied at the very rear of the bullet) and zero at the very front of the bullet. However, the average will be the same as what I used.

[BABore]

Do the lab tests enclose a lead boolit in a cylinder that is 0.001 to 0.003" smaller in diameter? Are the lube grooves filled with a non-compressible substance like boolit lube? Is the pressure applied in milliseconds at the start, then backed off? Is it done to proper simulate the forward motion of the boolit as happens in the bbl?

With a Welding Engineering degree and many metallurgy, Statics, and strengths of material courses under my belt, plus almost 30 years of experience, I understand and appreciate the subject here. I also understand that lab conditions and controlled tests do not always reflect life in the real world. Boolit hardness can be acheived from many directions. Linotype alloy is around 22 bhn air cooled. 50/50 WW-Pb, water dropped, is 22 bhn with my WW's. A 35/65 WW-Pb alloy with an addition of nickel babbit, water dropped, is also around 22 bhn. All the same hardness, yet do they shoot the same? No, not at all. Do they expand the same? Not even close compared to lino. Run any of these alloys up over 2,500 fps and your over your hardness limits in some cases, yet they behave very differently. Why? Cause there's more going on here than just a Bhn number. Boolit fit to the case neck, throat, bore, and groove as well as bore condition all come into play. How you launch the boolit is critical. Do you hammer it hard out of the gate, do you get it into the bbl a bit and hammer it, or do you get it into the bbl and gradually increase pressure til it peaks? Gas check shank length? Is it a stepped shank? How deep, how long? Size, depth, and position of the lube groove(s). All this has an effect in how it happens in the real world. Why does my 44 SBH shoot a 10 bhn boolit with the best accuracy at full pressure and velocity? Why does my 41 SBH only do the same with 22 bhn boolits? Why does my 480 Ruger SRH allow me to shoot a mixed cylinder of 10 and 22 bhn, plain based boolits to the same fine accuracy of either one individually? At 48 kpsi? To the same POI no less. Why is it that I know many serious casters that can do the same things that are outside the lab?

IMO, hardness is just a number. I know its meaning and know how to get there. I also know how to cheat the hardness/pressure formula in many cases. It's something I keep on file to use to my advantage when needed or desired. It's not something I fence myself into and marry.

[Bret4207]

Thanks BA, you put it far better than I could. No offense to anyone involved, it's just that there's more going on here than just a Bhn.

[45 2.1]

Thanks BA, you put it far better than I could. No offense to anyone involved, it's just that there's more going on here than just a Bhn.

And a formula that can be beaten by several people here.

[odoh]

Is the http://www.sixshootercommunity.com/h...etcasters.html link working for others? I get msg server is down ~ from http://guide.opendns.com/main?url=www.sixshootercommunity.com

Seems like this is a meaningful thread . . . worth following

[mrbill2]

I wanted to read this thing, but the link it's not working.

[onesonek]

Well,,,,,I understand the engineering mathmatical science behind the bhn/pressure thingy. But while new to casting, with 35 +yrs of reloading behind me, one thing I have learned,,,,,there seem to be no absolutes. I can readily see and understand Bret's and BABore's points.

[357shooter]

Added later: Everything I write say and think is limited to revolvers, specifically 357 magnums.

The engineering and math is fun to read about and for discussion. However taking it to the range an validating something like "matching pressure to BHN" to me is the tiebreaker and either validates the concept or not.

The only reason I even bring it up is there are enough articles an books about this that get read and then recited as truth. Sometimes here, often on other boards, many people are trying to figure out whats wrong with their gun because of their bad results at the range.

I don't claim to be able to explain all that happens to the bullet, and actually don't really care that I can't. I have proven beyond any shadow of a doubt that, first, the most accurate boolit in my 357 magnum is:

30,000 PSI with BHN 7-8 (< 1inch groups)

The most accurate BHN with other pressures (slightly bigger groups by .25 to .5 inch bigger at 25 yards, <1.5inch groups) are:

10,000 PSI with BHN 7-8
20,000 PSI with BHN 7-8
34,000 PSI with BHN 7-8

Also added later: other BHN opens the groups and are less accurate for each of these loads. The harder/higher the BHN the bigger the groups.

This is a rhetorical question: Shouldn't the results speak for themselves. I'm not claiming that BHN 7-8 is the most accurate alloy in every gun, and agree that there are many other factors are at play.

I'm not trying to disrespect anyone or be rude, but I do think the several thousand boolits of testing across alloys, moulds, OAL, etc... did provide a result that is valid. I also acknowledge that starting testing after reading the Lee book and accepting this "matching connection w/pressure" concept as valid caused me to spend many hours and many boolits trying to figure out what was wrong with my boolits, my gun, or my casting approach. In hindsight it was a good learning experience. But I wish someone just let me know up front...

I'm hoping to add to this discussion, not drag it down as this site is where I've learned to cast and have respect for all the folks here.

[Bass Ackward]

After all the fullin around I have done, I'm all over the map. Probably more ignorant than when I began this journey. Rifles for me tend to be logical and fairly predictible. Handguns there is no logic or pattern.

I use lino for low pressure 38 Special and 45 sometimes and 20-1 sometimes for high in different cartridges like 357 an 44. And thank God this fits my style. Allot of folks know that I mold all winter, but often my interests change that year and I run out of something and have to get by with something else. Some of my most biggest surprises are loads that are "worked up" for other guns and I accidentally grab the wrong shells when I went out.

After all the education and logical deduction, especially when you have to many guns to try every combo, it is my Forrest Gump style that gets me through at times.

[felix]

Don' feel like the Lone Ranger. ... felix

[Harry O]

prgallo: I also did some testing before deciding that this worked for me. I didn't just pull this out of my a$$.

It was in a rifle, a 1910 Mannlicher-Schoenauer in 9.5x57 MS caliber. I had to do this because the ONLY bullet that would feed properly from the MS magazine was a Lyman 375167. That is a PLAIN BASE bullet, with no provisions for a gas check. I knew that I would be limited on speed, but I did not know how much.

The first group I cast up was about Bhn 15. I loaded up a bunch from 42gr to 48gr of IMR4064. The groups were poor from the start. I went back and loaded up some more from 32gr to 42gr. Groups were fair at the start, but the accuracy abruptly took a nosedive shortly after I started and the barrel started leading a couple of hundred fps above that.

I heat treated the same batch of bullets and got them up to Bhn 20-22. Loaded them up again and tried them at the range. By increasing the hardness by nearly 50%, I only got the velocities up about 200fps. Interestingly, the leading started showing up AFTER the accuracy took a nosedive again, not before or at the same time.

I later went back with the loads and velocities I got from these tests and figured what the pressure was (with a Powley Computer). The pressures where the accuracy took a nosedive were very close to what the Bhn x 1422 number predicted.

I am shooting a 375167 right now that is cast and heat treated to Bhn 37-39. I can go to full loads with that one. If I had started out with that, it would have saved me a lot of time and effort.

[357shooter]

prgallo: I also did some testing before deciding that this worked for me. I didn't just pull this out of my a$$.

It was in a rifle, a 1910 Mannlicher-Schoenauer in 9.5x57 MS caliber. I had to do this because the ONLY bullet that would feed properly from the MS magazine was a Lyman 375167. That is a PLAIN BASE bullet, with no provisions for a gas check. I knew that I would be limited on speed, but I did not know how much.

The first group I cast up was about Bhn 15. I loaded up a bunch from 42gr to 48gr of IMR4064. The groups were poor from the start. I went back and loaded up some more from 32gr to 42gr. Groups were fair at the start, but the accuracy abruptly took a nosedive shortly after I started and the barrel started leading a couple of hundred fps above that.

I heat treated the same batch of bullets and got them up to Bhn 20-22. Loaded them up again and tried them at the range. By increasing the hardness by nearly 50%, I only got the velocities up about 200fps. Interestingly, the leading started showing up AFTER the accuracy took a nosedive again, not before or at the same time.

I later went back with the loads and velocities I got from these tests and figured what the pressure was (with a Powley Computer). The pressures where the accuracy took a nosedive were very close to what the Bhn x 1422 number predicted.

I am shooting a 375167 right now that is cast and heat treated to Bhn 37-39. I can go to full loads with that one. If I had started out with that, it would have saved me a lot of time and effort.

I have no doubt it works in a rifle and have never disputed that at all.

I've only disputed it fr pistols and more specifically 357 magnum revolvers. As stated in the 2 posts I've made.

I don't recall the article making the distinction between the 2. Sorry if I just misread and misunderstood what you said. When I tried to reread the article is gave the 404 internet error.

Are you stating all this for rifles only? I'll butt out in that case as I have no experience, opinion or interests in long guns.

[HangFireW8]

I am convinced that pressure rise time has as much or more to do with the problem of obturation, deformation and accuracy as the single variable of peak pressure.

I don't think I'm the only one, as there has been much discussion on this board of spanking hard boolits to get them to seal with faster powders, long slow pushes with extra slow powder for accuracy, etc.

I started out with the Veral/Lee formula and had (mostly) really good luck with it. Then I violated the rules, first unintentionally and then intentionally, and had some good luck (and bad) with that as well (both handgun, rifle, plain base and GC).

Now, when I start with a new combination, I mix up a melt according to the 90% deformation rule and work from there. Where I end up depends on my results, not the rules.

-HF

[Bret4207]

I won't disagree that general guidelines work fine with cast. I just believe there are variables and exceptions that rule out most hard and fast rules ( no pun intended).

[Harry O]

I won't disagree that general guidelines work fine with cast. I just believe there are variables and exceptions that rule out most hard and fast rules ( no pun intended).

This is something we can agree on. There are no "hard and fast rules" in most things, especially casting. However, this is something that will always work. It may limit an experienced caster, but it will work. That is something that beginners can use and rule out at least one reason for failures. Doesn't anyone else here remember failures when they first started casting and wondering what, out of all the possible reasons for it, what happened? When you get more experience with casting, you can SOMETIMES break the rules and get away with it. Other times, you can't.

As far as handgun vs rifle rules, I cannot speak with any authority on that when the rules are broken. I have not done any extensive testing with handguns. However, I know that when I follow the "rule" with handguns, I don't have problems. With rifles, I have done several tests after the one I detailed above. The rule has proven to be true for every test I have done. I have not had any luck finding out how to break the rule yet (in rifles). Everything I have tried above Bhn x 1422 has failed. Sometimes spectacularly.

That also means that I have had to do some experiments with very hard lead (above monotype at Bhn 28). They appear to have some rules, too. No need to get into that now, though.

[1Shirt]

Think along the lines of Bass and Felix. Been following this thread to the point where I can't remember all of the back and forths. Hated anything in school that resembled any form of math, and formulas etc. so have avoided it/them when it came to casting. The exception being Bh on my cabin tree, and readings on my chrono. I cast hard, water drop, and am sucessful at least in my own mind. I like bh in excess of 22, and vols between 1600-1800 fps for rifle, and 1000-1200 in handgun ctgs. I enjoy casting, sizing, lubeing etc. but I enjoy shooting more which is the reason I cast. When it gets to textbook for me, kind of back away.
1Shirt!:coffee: