Head scratcher: How does lube work?

[catboat]

I've been asking myself this question, and I'm not sure if I'm any further ahead as a result. It at least passes the time while I'm driving.

I've read that bullet lubes (and lube grooves) get "shoved back" or "Squeezed out" of the bullet grooves due to the extremely fast acceleration upon powder ignition. I have read that lube grooves on bullets may have some benefit to not be square in cross section, but angled back ("V shape" to some degree) or round, to facilitate the "the lube squeeze" out upon "detonation acceleration."

Here's why I started to think more to it. Upon powder ignition, gases expand and the bullet accelerates forward. Does any of the lube get "pushed forward" by the gas (as in gas blow by / gas cutting) that would lube forward?

I look at various bullet designs and wonder how they work. First, is a "true Keith" bullet. Square lube grooves, and 3 equal groove-deep bands. The lube goove is behind two of the leading bands. In essence, you are only lubing the last 1/3 of the bullet. What is lubing the first two bands? Why no leading? Is this due to "gas push forward" or "gas cutting" lubing? I don't know.

Then I looked at some cast bullet designs (I'm playing with some online designs at Mountain Moulds for a 9.3/.366" ~ 250 - 300 grain gas check bullet for my 9.3x62). I has a short neck (as does the 35 Rem, and 300 Savage which I also have). How do you have a large bore riding surface, and avoid leading?

So I ask the distinguished readers of castboolits.com to shed their views. Just how in the world does lubing work? If you can NOT lube for 2//3 of a Keith bullet, and only lube the bottom third of the bullet, there must be some other factor involved. Maybe there is something to a tumble lubed bullet.

If the only factor in lubing was the "acceleration squeeze out" factor, you'd think a lube groove pattern that has WIDER grooves up near the crimping groove, and then narrower lube grooves as you get toward the base of the bullet would make the most sense.

Enlighten me.

Thanks in advance.

[jonk]

Dunno, but it doesn't all get thrown out- I've recovered bullets from the dirt with plenty of lube still in the grooves.

[chevyiron420]

i have always kinda thought that the first boolit gets down a cold barrel with some luck and leaves some lube behind it, then each boolit after that gets the lube from the one before it. probably wrong, i dont know, but i dont get the LLA at all. i have 200 boolits for my 44 lubed up with LLA drieng now and have no confidence in them at all. im going to tumble them a second time today for good measure.-phil[smilie=2:

[4060MAY]

this is one of the few explainations that makes sense

http://www.lasc.us/FryxellLubeCastBullets.htm

[Blammer]

good read!

[9.3X62AL]

I have likened the action of boolit lube to that of motor oil in a car engine--that it serves as a bearing surface friction shield, and to assist in sealing the propellant gases behind the boolit base and drive bands. Think of the drive bands as piston rings, and the barrel as a cylinder.

Regarding your 9.3 x 62 boolit project, my rifle is a CZ-550, and its throat showed roughly .300" of leade clearance before rifling began. I used the MM software to slightly tweak the .366" 270 grain "default" pattern on Dan's program, which derives from a design produced by "Eirik" on Accuratereloading.com. I took the caliber's neck length + leade clearance and created a driving body of .600". The resulting boolit shoots 1.125" to 1.25" 3-shot groups at 100 yards, 23.0 grains of 2400 giving 1750 FPS, and has no part of the boolit base protruding into the powder space.

[Freightman]

I use teflon tape on my 45/70 wraped to the top of the lube grove and shoot it with a 450g Lee FNGC boolit have never had any leading. My point there is no liquid to pump, so how does that figure in the pumping theory? The 450 g boolit crno's at 1480+ fps. I also use LLA with no leading and 50/50 bees wax and LLA no leading. I have used the teflon on 8MM 308 311 with the same results (a little harder to wrap) but no leading.
How does lube work? I do not know but will worry about it when it doesn't work.
Printed off the artical and put it in my note book, knowledge is worth saving for future study. Thanks for the link

[arkypete]

That's one of those questions that reminds me of a joke.
Seems that one of the major networks wanted to find out what the common people were thinking, so they sent thier best story finder out to the hinterlands.
So this hotshot walks up to a county fella and asks 'What's the most interesting invention of the 20th century?'
Well the country fella ponders and ponders, then answers 'The thermos!'
'The thermos ?' says the hotshot.
'Yup!' replied the country fella.
This really intriques the hotshot and he asks 'How So ?'
'Well says the country fella "The thermos keeps hot things hot and cold things cold.'
'Sure does' says the hotshot.
The country fella continues "How do it know?'

Jim

[Bass Ackward]

I have been thinking on this since the last major discussion we had over lube. I have always destroyed the theories of others when examples could be produced, but never offered one of my own. You have to realize that there many different firing scenarios from shooting bore sized, gas checked bullets in a handgun to a throat choked rifle bullet that is sealed from gas at the get go. Complete seals can be established to none at all. And any lube theory must stand up to explain all situations. There are usually two theory camps. The hand gunners who tend to be Lube Sealers or Lube Pumpers. Or the rifleman and Lube Lubricators or Hydrologists of which I was one. Neither camp is correct.

So here comes my NEW and UPDATED rational.

1. I know that lead has a poor heat transfer rate which is the reason that surface friction can cause melting and thus leading.

2. I know that all lead that comes in contact with a bore will encounter frictional forces from either pressure, acceleration or rotation that will cause heat. Unless prevented, friction will eventually cause enough heat to cause melting described in 1. above.

3. I know that all lubes, no matter what they are made of, melt under heat. No matter how hard they are, this melting turns them or portions of them into a liquid state. There are three properties of liquids that apply here. A: All liquids can NOT be compressed by any force known to man. B: All liquids expand when heated. C: All liquids transfer heat very rapidly like dunking a hot iron in water or oil.

4. The slipperier a lube is, the less friction (heat) will occur under every possible firing scenario.

5. The harder a bullet is, the less friction from deformation or obturation will occur. As a side note: the harder a bullet is, the more spring back it will have to maintain contact over distances of dimensional imperfections that is within the bullet's ability to expand.

6. The smoother and more dimensionally correct a bore is or becomes over it's life, the less friction (heat) it will generate and the better seals it will maintain. Therefore, a smooth and dimensionally correct barrel allows the use of weaker lubes or softer lead at the same pressures or higher pressures and velocities with harder lead than it did before.

These are the factors we work with or around when we work with cast. Paper patching or taping prevent heat transfer from metal to metal contact, so less friction (heat transfer) means less need for lube or none at all.

Here it is: THE PRIMARY PURPOSE OF A LUBE IS TO WISK AWAY HEAT FROM METAL SURFACES. How much lube is needed is that amount or quality to handle the heat created by your firing situation. If barrel heat is suddenly raised, then more lube or higher viscosity lube will be required to prevent leading. The same load in freezing conditions might get away with half the lube or a less persistent lube. Yep. There it is in a nut shell. Lube isn't just a lubricator. Lube isn't just a sealer. Lube is a heat sink!!!

A second benefit of lube can be to hydraulically maintain bullet shape if in sufficient quantity to prevent friction from obturation. The larger the quantity that can be trapped, the greater the heat transfer capability. (A thimble full boils faster than a big pot) This hydraulic condition would be impossible to maintain in handguns with all the failures of bullet support and seals that occur at the B/C gap, Then pumping of the remaining lube will be the only hope. But hydraulics can be maintained under rifle like conditions. Thus rifle like conditions allow higher pressures and velocities with the same lubes and hardness used in a handgun situation.

And the third purpose for a lube is obviously to cut friction and therefore minimize the amount of heat that needs to be transferred or whisked away from the lead AND the barrel steel.

I think this .... combined theory explains why lubes or materials that are not even thought of as lubricants, like LLA, can function under certain situations. And it explains how important bore condition is to this balanced equation. It also explains why these non-lubes CAN fail before other lubes, if ideal bore conditions break down. It all depends on the firing conditions. A lube works, or it fails.

Non-lubricating lubes can perform the primary function which is to liquefy and absorb heat. And under certain conditions of smaller micro bands, they can maintain some hydraulic integrity. Understand they don't have to perform as much hydraulically because surface lubes (LLA) are generally used on stronger bullet designs. (Those WITHOUT deep, weakening, lube grooves.) When these type lubes fail, it is because they provided less lubrication to minimize bore friction and were used up by thermal breakdown before the bullet exited. (Ever hear that LLA smokes heavily under pressure?)

So as long as bore condition and dimensions and lead hardness and bullet design and controlled pressure (what ever level that is) and temperature both of the barrel and externally, can be controlled by the .... heat transfer rate of ANY lube, it works, and leading is prevented. When one or more of these factors are over come, and the lube cannot control friction, or dissipate the heat before the bullet exits, the lead is melted and left in the bore.

Expansion of lube from heat will eventually turn it into a gaseous state itself which I'll call thermal breakdown. This can explain why ANY lube smokes under pressures (that are extreme for it) just before it fails. When lube is left in the bore, the affect is additive and available to the next bullet to prevent friction, and thus heat, which is why some lubes don't perform well until a build up or a blackbore condition is established. This also explains why we need less lube in the winter as temps drop and heat is less of a factor. And why Felix always talks of viscosity or lubricity for the pressure application under which the will be used.

Well, it's hanging out now! :grin: Bed time after this.

[buck1]

I'm sold! Great post Bass !.....Buck

[357maximum]

Bass

did that hurt?

[9.3X62AL]

Bass--

Your post makes a LOT of empirical sense. If what you say here ever turns out to not be true, it still oughta be.

[carpetman]

Bass--I agree with a lot of what you say. I don't buy lead melting in the barrel as it's just not there long enough. If it would melt lead during that very brief period--it would melt the lube and a bullet spinning as fast as it does this liguid lube would be flung off,more so than a dog shaking off water and there would be no trace of lube to be found on a recovered bullet. But the inverse happens. Lube is still on the recovered bullet most of time in same shape as when applied.

[joeb33050]

Cast bullets that are small for the barrel will lead, lube doesn't help. Shoot 30 caliber lead bullets in 30/40 cases in a 40-1 7/8" Sharps while case forming if you want to see some lead in a barrel.
Cast bullets that are large for the barrel won't lead. It requires an extreme load to get .312" cast bullets to lead in a 30 caliber rifle. Big bullets almost always shoot in any gun, smaller bullets sometimes shoot.
Cast bullets with no lubricant will not lead with Cream of Wheat filling the case from powder to bullet base. No lead, none.
Norm Johnson shoots unlubricated cast bullets in revolvers, without leading, as his normal loads. Not experiments, every day shooting. He says it's all about dimensions of the bullet and the gun.
I shoot bullets with no grease grooves but with Darr lube or LLA, and no leading, so it doesn't required grease grooves to shoot without leading.
Most recovered cast bullets that I've seen have most of the lube still in the grooves.

I don't know what lube does on a cast bullet. I suspect that it does more sealing than greasing.
joe brennan

[arkypete]

I don't know what lube does on a cast bullet. I suspect that it does more sealing than greasing.
joe brennan

Joe
I'm with you.
I've thought that if I could inject nylon, some sort of plastic into the grooves of a bullet I would achive the same effect as the various greases and waxes.
Something like the rings on a piston.
Jim

[Whitespider]

This whole discussion reminds me of a theory my boss has. I work in wireless communications. What that means is, I climb communication towers to install and/or maintain radio equipment. Over the last few years, radios and antennas have become smaller and very sophisticated. Sometimes, when a new product appears, we’ll look at it and question, “How can that work?” My boss always says, “It works on the FM theory”.
Now, understand that we DON’T work with FM band radios, we use microwave high frequency equipment. Well, after several years of hearing about the “FM Theory”, I finally got up enough nerve to ask him what the “FM Theory” was.

He looks me square in the eye, smiled and said, “It’s a F@#king Miracle!”

[Maven]

Bass, et al,

"A second benefit of lube can be to hydraulically maintain bullet shape if in sufficient quantity to prevent friction from obturation."

Is this also why a CB with all its lube grooves filled (with lube of course!) can be substantially resized without deformation and loss of performance? Elongation, yes, but as long as the sizing die v. ram v. press (Lee push-through sizing dies) relationship is concentric (co-axial?) there's not much deformation. Buckshot first tried this with excellent results. I repeated it with the same effect.

[9.3X62AL]

FM Theory--too funny.

Joe, I think you summed up my take on the matter in your final sentence pretty succinctly.

[Bass Ackward]

Paul,

Of coarse. A bore is nothing more than an elongated sizer.

All,

I just feel that things, like shooting, like lube, can not be explained entirely. I doubt that they ever will be because just like there are no fact to shooting, there are no set conditions to define what a lube must do. You have to be able to visualize many different scenarios and put them all together. And you can still find contradictions.

My point was that people who believe in sealing are confused. There are bazillions of examples that counter that one that I am amazed it still has any followers. Same with the lubricator theory. Just look what normal seasonal weather does to those theories. In the cold, you don't need as much lube to seal? If sealing explained everything, then the same amount of "sealant" would be required year round. And using too much sealant would not have negative effects to cause sealant fliers. The only thing that changed was temperature levels and how much heat needed to be whisked away.

And Joe, the first shot in a clean barrel should seal just as well as the rest. Therefore, there would be no need to have a "Fouling Shot". So a whole magazine is improperly named if the sealer theory is true. And one sealant that seals, should be as good as the next, so we all should need just one kind.

Nope, no one theory can stand alone. But a combination of all three liquid properties, seal, lubrication, and heat sink, goes the farthest I have seen to explain things.

Hope it gets some minds to thinking but doesn't cause catboat to veer off the road. :grin:.

[Glen]

Heat transfer theory, huh? I'm not sure I buy that one. Ignoring the kinetics of heat transfer for the moment, let's just look at the components of the system -- the bullet, the barrel and the lube. The mass (and heat capacity) of the barrel, as well as the mass (and heat capacity) of the bullet so significantly outweigh the miniscule mass (and heat capacity) of the lube that it's just not a horse race. If the heat transfer model were accurate, then the lube would have to soak up so much heat that it would likely vaporize at the muzzle. I've recovered too many fired cast bullets that stil had lube in their grooves to place much faith in this theory.

The lead that gets deposited on a bore does not get there from melting. It gets there from ablation (also called gas-cutting).

I agree with you that one theory alone does not explain how lube works, but that doesn't mean that lube doesn't help to seal the gases in a cast bullet load.

[Bass Ackward]

Heat transfer theory, huh? I'm not sure I buy that one. Ignoring the kinetics of heat transfer for the moment, let's just look at the components of the system -- the bullet, the barrel and the lube. The mass (and heat capacity) of the barrel, as well as the mass (and heat capacity) of the bullet so significantly outweigh the miniscule mass (and heat capacity) of the lube that it's just not a horse race. If the heat transfer model were accurate, then the lube would have to soak up so much heat that it would likely vaporize at the muzzle. I've recovered too many fired cast bullets that stil had lube in their grooves to place much faith in this theory.

The lead that gets deposited on a bore does not get there from melting. It gets there from ablation (also called gas-cutting).

I agree with you that one theory alone does not explain how lube works, but that doesn't mean that lube doesn't help to seal the gases in a cast bullet load.


Glen,

Think about this.

If you have lube left in the grooves, that means that all the forces you mentioned didn't do their job at pumping lube what so ever. So where was the seal? And where did the lube go?

If lube were liquefied it would flow under those conditions. In the summer, more would be used up and the winter you would find more on the bullets. That's how my handgun stuff is. So why is that? Same load. Same rotational and acceleration forces. Just less heat to melt my lube is why. Rifles I never find any. I am RPMing those babies to death. For handgun bullets a general rule of thumb is that hard lubes are bad and soft lubes are good. Not all cases ............. but softer lubes would flow faster as they made more surface contact.

And as far as lube vaporizing, how IS lube used up? Ever watch a guy pushing his limits using the same lube as you? Almost all lubes smoke just before the end. And you match the viscosity of the lube to the pressure and conditions it must endure. Otherwise one super hard rifle lube should work under all conditions and NEVER break seal or lead at handgun velocities. You know no one lube fills all conditions.

The liquid theory supports seal, lubrication and changes in temperature or heat. Liquids boil off. The smaller the water drop the faster it heats and boils off. It can't boil off if it didn't absorb heat. That's where viscosity comes in. Racing cars have pistons and seals, but need heavier oil than passenger car engines not to break down huh? Just watch the Pennzoil commercial on TV. They talk about how their molecules recombine to counter shear forces and heat.

Remember, lead has a poor heat transfer rate, that's why it flash leads. There are two types of leading. Gas cutting and flash leading. Don't think so? How can you possibly have gas cutting in the taper of a taylor throat when that bullet is constantly sizing and getting smaller? You can't. Impossible! Especially at handgun pressures. That is frictional or flash leading. Gas cutting occurs after that. As a bullet begins to pass lead deposits, it has to size down. Once passed that point, there is your seal loss occurs. That is where gas cutting begins. BUT the cause was the flash or frictional leading.

But as far as mass goes with lead I believe it's insignificant because of the transfer rate problem. Only surface area and viscosity matters. And liquid lube will be covering that same area. If the viscosity matches the heat, it will endure, it will prevent friction, absorb the heat, and the seal will remain intact.

It has to, that's your seal.

[Glen]

BA -- I agree with you that the lube minimizes the frictional heat generated by the bullet by lubricating its passage. I just don't believe that frictional heating is sufficient to melt the lead.

You asked where does the lube get pumped to? As was covered in the article, it gets pumped to the gap between the trailing edge of the land the surface of the engraved bullet (as well as any other microscopic defects in the bullet's surface as a result of engraving). These are very small, but with 20,000-30,000 psi pushing on the base of the bullets, these defects represent a significant leak for gases (the much more viscous lube can't leak out as quickly). If these defects are too large (e.g. from an undersized bullet), then the lube gets pumped (OK, blasted) out in front of the bullet, you have a naked bullet and you get severe leading as a result of the ablation from the gas leakage.

The fact that there is lube left in the grooves does not mean that it wasn't pumped. Does the fact that there is gas in the tank of your car mean that the fuel pump doesn't work? Of course not, it just means that it hasn't had enough time to pump the reservoir dry yet. The same holds true for bullet lube and pumping mechanisms.

You CAN have gas cutting in a taper bore -- again, the focus for how a bullet seals is not on bullet diameter, the focus is on the trailing edge of the land (the leading edge of the land is sealed by the bullet's inertia forcing the bullet metal onto the land, but the trailing edge has not such guarantee, and miniscule variations in the width of the land results in this contact face being the weak link in the seal).

[looseprojectile]

Some time ago I was having some trouble with boolits sticking in the sizer die.
I mean really stuck. I then pre lubed the boolits and got some relief. These were RCBS CAS 300 grain .410 dia. for the 40 65 Cimarron highwall.
I have always pre lubed the bore before firing the first shot with bore butter.
Bass has said the bore is similar to a sizing die.
When using softer alloy or pure lead there is no tendacy for the boolits to stick in the size die. Now I wonder if those hard boolits tended to stick in the bore of the rifle also. How could I expect those hard boolits that stuck in the die to sail slickly through the bore of the rifle?:roll:
I have recently quit making my boolits so hard and have had better results.
I like fairly soft lube and almost any lube will work well at less than 1600 fps.
I have recently acquired a vintage, 1921 saddle ring 1894 Winchester in 30 WCF and have had good results with softer alloy and softer lube up to 1800 fps. with the gas checked 31141.

I hope this makes sense to you!:hijack:

[Bass Ackward]

BA -- I agree with you that the lube minimizes the frictional heat generated by the bullet by lubricating its passage. I just don't believe that frictional heating is sufficient to melt the lead.

You CAN have gas cutting in a taper bore -- again, the focus for how a bullet seals is not on bullet diameter, the focus is on the trailing edge of the land (the leading edge of the land is sealed by the bullet's inertia forcing the bullet metal onto the land, but the trailing edge has not such guarantee, and miniscule variations in the width of the land results in this contact face being the weak link in the seal).


Glen,

OK. I see the issue. You do not acknowledge that flash leading or galling exists. You may not acknowledge that lead is a poor heat sink because the surface melts while the core is still cool. You have never worked with lead bearings have you? :grin: Ok. here goes.

Definition: A condition whereby excessive friction between high spots results in localized welding with subsequent splitting and a further roughening of rubbing surfaces of one or both of two mating parts. From the link below.

http://metals.about.com/library/bldef-Galling.htm

If it helps don't think of it as melting, just welding.

Prove it to yourself.

Do an experiment for me. Take a hollow base bullet or drill a hole in any bullet design. Fill this space with soft lube. Any lube. Size this bullet to the same size as the throat on any handgun. Shoot that bullet at any reasonable pressure into something you can recover it from. Guess what you will find? That the lube will still be there. Intact. Perfect. Now repeat the test and size to bore. Use a hard bullet at too low of a pressure so the bullet will take time to obturate. Fire that and recover that. The lube will be gone.

What's my point? This will show you that the heat from the expanding gas only melts lube or cuts lead if it can pass under pressure. If hot gas can't melt bullet lube, how is it going to melt the trail edge of a land that is still sealed? Even if that land fails, there are more bands ahead of it maintaining the seal. Without a barrel imperfection, the only way they can break seal is to gall. So if you can't melt lube under a seal, how are you going to melt lead?

Want to know how easy it is to melt lead? Buy a Lee push through sizer. On the instructions it used to show a lead bullet melting away under the lube with a torch. Now you will understand the limitation to LLA. It transfers heat too fast that the lead is still melted and deposited. So LLA is prone to frictional leading or galling which is why you must use harder bullets with LLA than other lubes because harder bullets resist friction better.

Want another test? OK. let's eliminate gas all together. Take a bore of any gun and degrease it. Take an ACWW bullet and start it from the muzzle without lube. drive it through as fast as you can. Even at that rate without any gas to cut, you will have lead galled to the bore. Smeared, welded, .... galled. Right .... before .... your .... eyes. And zero gas to cut anything.

Want more proof? Take a safe load of slow powder and fill the case with Cream of wheat. Place an unlubed ACWW bullet over it and shoot it. The cream of wheat will act as the seal. Norm Johnson does this all the time. If there is no such thing as galling, you won't have any lead. But I will bet that you do.

Want another? OK. take a shotgun shell and cut the plastic cup off the wad. Place that back on the powder and fill the shot again. Shoot that in a dry, clean bore. That plastic cup is going to maintain a gas seal. Got any lead in the barrel? :grin:

It happens! Once in the bore, a bore sized bullet must size over it to pass. THEN and only then CAN you get gas cutting!

[Glen]

OK BA, I will try to take your points on one at a time:

I never said anything about galling. I firmly believe that galling is an issue, I only stated that I don't beleive that frictional forces of the bullet's passing are enough to melt lead. (Yes, I have worked with lead bearings, that has virtually NOTHING to do with lead bullets melting as lead bearings are under contiuous friction for extended periods of time, while bullets only experience them for 1-2 milliseconds).

OK, concerning your experiment with a HB bullet filled with lube -- have you ACTUALLY done this experiment in a revolver? When that HB filled with lube blows past the cylinder gap, the lube is going to get blown out the gap, whether the bullet is soft or hard. Do it in a sealed breech (e.b. semi-auto), and the lube has nowhere to go and will stay in the bullet. This experiment has nothing to do with the issues I brought up earlier.

But I will follow your lead here --if hot gas can't melt bullet lube (with a melting point of maybe 120 degrees F) how is it going to melt some lead alloy (melting point of 500+ degrees F). The Laws of Thermodynamics don't take vacations.

I never said anything about melting the trailing edge of the land, you did. I simply said that the escaping gases would ABLATE the lead off of the bullet as they blew past through the leak. Melting is a different phenomenon.

"Without a barrel imperfection..." -- that is the key to my point, barrels, as good as they are, are not perfect when viewed at the molecular level (which is the level we have to look at when we talk about keeping all of the gas molecules BEHIND the bullet). Even defects as small as .0001" (which is VERY good machine work) leaves enough room for 50,000 gas molecules to blitz on through, unimpeded.

LLA isn't lube, it's a varnish. Nuff said.

As for your next "experiment" -- I have fireformed wildcat cases with cast bullets using unlubed bullets at 1600-1800 fps with no leading whatsoever (accuracy was aweful, but there was no leading). Gosh, I guess "frictional melting" must have taken a holiday, right?

Your last two experiments exemplify exactly what I'm talking about -- a good gas seal helps to prevent leading. As for your closing comment, I haven't deciphered that one yet to figure out what you're trying to say....

[felix]

ab·late: To remove by erosion, melting, evaporation, or vaporization. From this definition, it does not matter how the edges actually get blown away down the barrel. We just know it does when the boolit is just not right for the circumstances. ... felix

[leftiye]

I kinda like Felix's approach here. It does happen.

Gas cutting does happen. It probably doesn't have anything to do with lube, except possibly if the lube can seal the interface between a bullet, and bore. Otherwise gas cutting progresses apace.

Friction does happen. Contrary to what has been said this has to be EXTREME! It should produce muy mucho calor, y muy pronto. Avoiding this happening is nothing short of a miracle. Remember that heat from friction increases with (at least) three factors- pressure of contact, drag of surfaces, and velocity. This in the case of a boolit is nothing to sniff at. If this heat doesn't transfer away due to lead not carrying heat well, then the only other things that can happen are either for the surface of the lead to melt, or for something like lube to absorb the heat (and possibly vaporize). I'm of the opinion that the reason that copper plated boolits loose their plating at higher velocities is that copper conducts heat well and melts at a higher temp than lead, and therefore it takes the heat of the friction to the lead core. The lead melts, and the boolit loses its plating.

Galling isn't somehow a non phenomenon where lead, and steel mix. And it does invlove heat. It is the heat created at even almost zero velocity when the pressure goes through the roof. It occurs at the microscopic level, and welds or solders first two (one steel, one lead) atoms, then four atoms, and so on. Have you ever wondered how a snow covered road gets slick and icy? It's the pressure from the tires melting the snow so it can re-freeze as ice. Remember, where the tire meets the road it isn't moving. The same thing will happen where lead, and steel meet with no lubrication, and lead will be melted and applied to the steel (works really good with steel to steel too, - lots of pressure , not much velocity). More velocity? Then it works even better.

It's obvious that lubes can (and most probly DO) do any of the things laid out previously in this thread. They lubricate, they therefore reduce friction and heat and can stop galling if they're a good enough lubricant. They undoubtedly do some varying amount of sealing in the boolit bore interface, and there's nothing that can or would keep them from evaporating and cooling the surface of the lead. All that is needed is for the lube to be there, and for something to be hot.

[Whitespider]

Hmmmmmmmmmmm..........
I'm still thinkin' FM Theory!

[Boomer Mikey]

I was in the Two Way Radio business for over 35 years and explained the FM (Freaking Magic) theory many a time to our customers.

I shoot many Bear Creek Bullets with and without lube grooves up to 1800 fps with no leading that are molly coated and sealed with a proprietary covering of Teflon or paste wax (maybe both?).

The most significant reduction of leading problems and improvement in accuracy for me was the discovery that the largest bullet that will fit in the chamber usually works best, softer lead is better than hard lead at lower velocities, and smooth bores without constrictions aren’t fussy about lube or BHN.

I don’t really care if the bullet is lubed with molly, paste wax, Teflon, Crisco, Pam cooking spray, hard, soft, or no lube and I’m quite happy to call it “Freaking Magic” or anything else.

As long as it works I’m not going to loose any sleep thinking about it.

Boomer :Fire:

[joeb33050]

Ken Mollohan did a lot of work and wrote a lot about bullet lubrication in the book. See http://sports.groups.yahoo.com/group/CB-BOOK/, look in "FILES" for the book, then "5.0 Bullet Lubrication".
joe brennan

[Newtire]

i have always kinda thought that the first boolit gets down a cold barrel with some luck and leaves some lube behind it, then each boolit after that gets the lube from the one before it. probably wrong, i dont know, but i dont get the LLA at all. i have 200 boolits for my 44 lubed up with LLA drieng now and have no confidence in them at all. im going to tumble them a second time today for good measure.-phil[smilie=2:

Hi again Phil,

Give those LLA boolits a try with that double coat of lube and if they smoke too much and you have no leading, try a little less lube. I shoot that stuff in a .444 Marlin up to 2100 FPS+ and in .30-30 at 2300+ and don't get leading. They say, too much lube can be bad for accuracy but don't know about that. You might want to put a little LLA on a cleaning rag and run it down thru your barrel before you start shooting. Wipe it out clean (some will still be there) and you will have a pre-lube condition. Just like pre-lubing engine parts before you fire one up after rebuild.

[Bass Ackward]

As for your next "experiment" -- I have fireformed wildcat cases with cast bullets using unlubed bullets at 1600-1800 fps with no leading whatsoever (accuracy was aweful, but there was no leading). Gosh, I guess "frictional melting" must have taken a holiday, right?

Your last two experiments exemplify exactly what I'm talking about -- a good gas seal helps to prevent leading. As for your closing comment, I haven't deciphered that one yet to figure out what you're trying to say....


Glen,

I made the mistake of equating galling with melting. I do a lot of welding and soldering and equate heat as part of the equation. My error. The galling process is temperature related as I will use your example above later.

And yes. I recovered many of my bullets that had the lube still in the base of the bullet from the sizing process. This was entirely by ignorance. When I started casting back in the 60s, I used everything to include bullets with air holes in the bases that filled with lube from the sizer. If it was capable of going bang, it went down range.

I found out then that if lube was enclosed, heat and pressure and gases had no effect on it unless gases were permitted to escape, Then I assume that it melts and vaporizes or does something. I don't know how you would prove what happens and it wasn't really relevant to solving my problem.

That technique can be a quick problem solving tool. If I am working with a gun I am unfamiliar with it can eliminate gas .... escapes as a reason for leading if I can't diagnose the reason by some logic. I have had leading caused from blowing off the lube before it produced any visible signs of cutting on the bullet. The check was a quick down and dirty.

I use a lot of PSB. But from my results, solid filler is not a sealer unless so designed for the purpose like a shotgun wad. Solid filler transfers the obturation force from the base of the bullet to a material that will not lead. That's all as temperature will prove below.

I have shot unlubed bullets also. I did it with no lube using filler to protect the base, although not to fire form brass. And friction does come into play in loads without lube. Prove it to yourself. Take that same load that you fire formed with. Raise and lower temperature, and see if you don't move into the gall zone and lead. The softer the lead, the narrower the temperature change range. But the cold part with no lube is the puzzler. SO filler "seal" doesn't cover it either. :grin:

So I find it pays to consider temperature right up there with seal and lubrication benefits because it alters both of those factors. Of coarse the galling leaves lead deposits that attract more lead and eventually require passing bullets to size to get around it if the GC can't keep it at bay. When the bullet isn't hard enough to disperse it and can no longer spring back in passing or the pressure isn't high enough to obturate the base again to maintain the seal, gas cutting ensures.

[truckjohn]

I think we left out one significant reason that may also tie into the equation.....
Lube vaporizing and cooling the powder flame front.

Harold Vaughn published results about this in his "Rifle Accuracy Facts" book in the small blurb about Moly Coated bullets. Turns out that commercial moly bullet coating uses Moly mixed with beeswax -- to stick it on. He found that the beeswax vaporizing created a cooler flame front -- causing the lower initial velocities found when using Moly bullets with the same load as non-coated bullets.

What if one lube property is to cool the flame front a little along with all those other things.

As many have stated here, you can swage a grease grooved lead boolit into pretty much any shape you want -- so long as you fill the lube grooves you want filled when it is done. The unlubed grooves bump up to diameter, while the lubed grooves hold strong. This is enough pressure to swage a round nose into a SWC nose -- and no leading in the swage die if you use just a teeny bit of swage lube (lanolin + mineral spirits.)

Now combine everything we have mentioned: Flame front cooling + Vaporized wax + Bullet fit to barrel + Bullet base strength against obduration + Gritty powder and primer residue on barrel surface + actual lube sealing ability + actual lube lubricating ability -- we have a whole bunch of factors that create or reduce: Friction, Flame Temp, and Pressure.

So, we have a whole bunch of factors -- and some really smart people on the board. If we can figure out a good way to repeatably test factors against eachother, we can do actual experiments to quantify the strength of the factors against the effects.

Brainstorming Effects:
Velocity
"Leading" -- but how would we "measure" leading?
Group size (may be a problem because of other things going on)

Brainstorming Factors:
Bullet diameter
Lube flashpoint
Lube viscosity
Fillers/Cards/Wads under the bullet
Load pressure/powder charge

Please chip in with some more. I would like to get an experiment going to help myself understand this mess.

Thanks

John

[PACERR]

Good stuff.

I can only add one speculative comment. Friction and heat both add to temperature.

A 3000 PSI hydraulic system heats up quickly. Rubbing two cats together does too.

What's 13,000 or 30,000 PSI do to the other factors if even for a fraction of a second. Probably only affects the surface molecules during the time in the barrel but I haven't seen it accounted for in the discussion. Perhaps it's not significant?

[Bass Ackward]

I keep thinking about this and I want to go back to what a smart man for cast, named George Marshall once wrote that the best accuracy with cast came just before leading began. That sounds to me like he was saying that you needed balance in a bore at the velocity and pressure you were running. In a word, balance.

The problem with defining things can be in terminology. In cast bullets we have enough stuff already that is confusing. I incorrectly said melting for galling because in my mind that's how welding or soldering is done. We often talk of steel molds that are really iron. Bore and groove are another set that is sloppily used. Same with cylinders in a handgun when we really mean chambers. We get sloppy and in order to be precise, you have to correct. I think seal is one more of those terms.

How I look at bullet lube is that I use it to avoid that "perfect seal". A perfect seal is one which will not pass any gas at all which is the definition of a totally galled or stuck bullet. Lube is used to prevent that. So talking about seals can be confusing for some folks since how do you define a good seal as opposed to a bad seal? Temperature keeps good /bad in a constant state of flux .

I say that you need a film of lube that will prevent galling at the pressure and temperature range of interest under the conditions which you are using it. That it in a nut shell for me.

The seal that happens is a natural event that I am willing to accept happens because my bullet moves forward and out. At least it has so far. Even a bullet, thought to be without lube, has carbon in the bore that it uses to prevent galling or that "seal". And as long as you remain in balance, it will work. But that range of operation would be too limiting for the vast majority of us, so we use lube.

That was a simple statement for a remarkably complex issue that involves everything from fillers to bore condition. And since we can't define those as to good or bad, how do you define something that ties them all together to allow successful use of something prone to locking up? Good luck.

[S.R.Custom]

Reading through all these posts, I have to admit that my eyes glazed over about halfway through. While all the theories sound plausible on some level, no one really knows for sure, because a bullet speeding down the bore is not something we can stand there and watch in slow motion. When faced with an analytical problem where empirical evidence is nil, I tend to look for the simple explanation...

When you solder two pieces of metal together, say, an electronic component to a circuit board, you apply a substance known as "flux" to the components to aid in the bonding and adhesion of the metals. I think of bullet lube as the "anti-flux" to the bullet/bore bonding problem, because that's essentially what lead fouling is-- the bullet trying to bond to the bore.

When a bullet is forced down the bore with 20K psi of pressure behind it, the propellant gasses are trying to cut and rush past the bullet along the sides. When these gasses pass past the lube groove, they strip some lube away, and under that kind of heat and pressure, the lube being stripped away is most assuredly in a gaseous form. It's presence, co-mingled with the lead that's likewise being stripped from the side of the bullet, presents a fouling situation as far as the bullet is concerned, and keeps the lead from adhering to the metal of the bore. Hence the term "anti-flux."

I came to this conclusion a few years ago, and my epiphany resulted in a "what if" moment... If the protective quality of bullet lube is a result of its anti-fluxing properties, what would happen if I applied said lube to the bore of the weapon as well as the bullet? So I ran a wet patch of a mixture of mineral spirits and Lee Liquid Alox down the tube of a favorite .45 of mine when I cleaned it, and put it away, allowing the LLA to dry in the bore. What happened the next time I shot the .45 simply amazed me...

This particular .45, when shot with my most accurate load, would show appreciable amounts of lead fouling in about 100-150 rounds. With my "Bore Prime" applied (I've since come up with the ideal ration of 2 parts mineral spirits and one part LLA), fouling was non-existent until I'd run about 500 rounds down the pipe. And even then, whatever fouling that occured was easily stripped out with 2 or 3 passes of a tight fitting, dry bronze brush; the lead fouling came out in pronounced lead strips, as it had totally failed to bond to the bore in any meaningful way.

There is a "seasoning" process at work here as well. Any gun of mine that sees only lead bullets, and is cleaned thoroughly and treated with Bore Prime at clean-up, develops what I call a burnishing of the bore; the interval at which fouling occurs seems to get longer each time, requiring only a few passes of a dry brush to bring about a shiny clean bore until the point it rarely fouls at all. Sorta like that favorite .22 you never have to clean...

Is Bore Prime the magic elixir that ends lead fouling? Of course not. If you push a 240 gr. PB down the bore of a .44 Magnum with 26.0 grs of 296, you're going to have a mess regardless of what you do. And shooting jacketed bullets through a dedicated lead bullet gun makes for a real mess too, until you get all the copper out again. But Bore Prime does help quite a bit. Try it and see...

[BOOM BOOM]

HI,
I just had a chance to read this. It covers the subject of lube theory better than anything I have ever read before!
One point, some liquids can be commpressed ( but not at the pressure ranges we are talking about).

[Misfire99]

Reading through all these posts, I have to admit that my eyes glazed over about halfway through. While all the theories sound plausible on some level, no one really knows for sure, because a bullet speeding down the bore is not something we can stand there and watch in slow motion. When faced with an analytical problem where empirical evidence is nil, I tend to look for the simple explanation...

When you solder two pieces of metal together, say, an electronic component to a circuit board, you apply a substance known as "flux" to the components to aid in the bonding and adhesion of the metals. I think of bullet lube as the "anti-flux" to the bullet/bore bonding problem, because that's essentially what lead fouling is-- the bullet trying to bond to the bore.

When a bullet is forced down the bore with 20K psi of pressure behind it, the propellant gasses are trying to cut and rush past the bullet along the sides. When these gasses pass past the lube groove, they strip some lube away, and under that kind of heat and pressure, the lube being stripped away is most assuredly in a gaseous form. It's presence, co-mingled with the lead that's likewise being stripped from the side of the bullet, presents a fouling situation as far as the bullet is concerned, and keeps the lead from adhering to the metal of the bore. Hence the term "anti-flux."

I came to this conclusion a few years ago, and my epiphany resulted in a "what if" moment... If the protective quality of bullet lube is a result of its anti-fluxing properties, what would happen if I applied said lube to the bore of the weapon as well as the bullet? So I ran a wet patch of a mixture of mineral spirits and Lee Liquid Alox down the tube of a favorite .45 of mine when I cleaned it, and put it away, allowing the LLA to dry in the bore. What happened the next time I shot the .45 simply amazed me...

This particular .45, when shot with my most accurate load, would show appreciable amounts of lead fouling in about 100-150 rounds. With my "Bore Prime" applied (I've since come up with the ideal ration of 2 parts mineral spirits and one part LLA), fouling was non-existent until I'd run about 500 rounds down the pipe. And even then, whatever fouling that occured was easily stripped out with 2 or 3 passes of a tight fitting, dry bronze brush; the lead fouling came out in pronounced lead strips, as it had totally failed to bond to the bore in any meaningful way.

There is a "seasoning" process at work here as well. Any gun of mine that sees only lead bullets, and is cleaned thoroughly and treated with Bore Prime at clean-up, develops what I call a burnishing of the bore; the interval at which fouling occurs seems to get longer each time, requiring only a few passes of a dry brush to bring about a shiny clean bore until the point it rarely fouls at all. Sorta like that favorite .22 you never have to clean...

Is Bore Prime the magic elixir that ends lead fouling? Of course not. If you push a 240 gr. PB down the bore of a .44 Magnum with 26.0 grs of 296, you're going to have a mess regardless of what you do. And shooting jacketed bullets through a dedicated lead bullet gun makes for a real mess too, until you get all the copper out again. But Bore Prime does help quite a bit. Try it and see...

I would like to second the anti-fluxing argument. It's true we can't see what happens to a bullet that is traveling down the bore. But, using high speed photography, we can see what they look like when the are born into this world. I was looking through Lyman's Black Powder Handbook and they have some high speed photos of bullets fired from muzzle loaders. These are bullets that are traveling much slower then smokeless rounds. You can clearly see how the hot gases have eroded the base of some of the bullets. So it does get hot enough to melt the lead of the bullet.

I used to shoot IPSC with a 38 super. I bought my bullets from a guy at the range that had a secret "lube." I talked to him about it one day and he told me that the lube isn't really lubing anything. What it does is stop the melted lead of the bullet from soldering to the bore. His bullets had a hard black coating all over them. It looked allmost like a powder coat. I would push these pills to 1450 fps with zero leading. And judging from the blast out of the comp it was plenty hot inside the barrel to melt the lead. My 38 super wouldn't even run with store bought ammo. Just to get it to cycle you have to use "Hot" loads.

But what about paper patched and teflon taped bullets? I think the same thing applies. It is just that the paper or tape is physically preventing the lead from touching the barrel. This prevents it from soldering. So why doesn't the paper burn away if it's so hot? The paper is in direct contact with the barrel and the steel in the barrel is acting as a heat sink so the paper never reaches it flash point.

Well this is my opinion and that with a buck fifty will get you a cup of coffee.

[Lloyd Smale]

I puts it on my bullets and shoots dem!

[Milky Duck]

so..having read right through this thread...and got a headache ....what if any effect would dipping the boolit itself in ,say,vasoline or soft mutton fat/frypan grease,before chambering in rifle have??? would it be positive effect by sliding down into junction of boolit and barrel and making it slipperier??? of do you then risk the dreaded bulge the barrel???that shooting with oil or water in barrel is said to cause???

[Winger Ed.]

..what if any effect would dipping the boolit itself in ,say,vasoline or soft mutton fat/frypan grease,before chambering in rifle have??? would it be positive effect by sliding down into junction of boolit and barrel and making it slipperier?

I'd figure the front end of the boolit would scrape it off like a squeegee and it wouldn't really lubricate much at all.
But the added weight of lube or anything else in front of the boolit would raise the chamber pressure to one degree or another.

[Milky Duck]

yip that figures....but I wont know if dont ask LOL.

[Plugs and Muffs]

I recall an article a few months back, I do not remember where...the people shooting service rifle matches in the early 1920s, were having a bad build-up of copper in their bores. So some bright boy decided that if he dipped the nose of the jacketed round in grease, the copper fouling would be mitigated. Well to some extent it was, and the trick was passed around. The fly in the ointment was that the springfield's started to fail. Further testing showed the dreaded "low number weakness", and the fact that the more is better crowd combined it and generated 80,000 psi or more. About this time the metallurgy on the jacket mix was revised and the original problem was pretty well cleared up. The word got around and grease dipping ceased.

[firefly1957]

Plugs and muffs I remember reading about that years ago I think it was from Hatcher's notebook and if I remember correctly had something to do with tin?
I forget if the tin was in jacket material or was on it? Back then many bullet jackets were copper nickel alloy and looked like steel jackets .

Plugs and Muffs is How I shoot two of my pistols a .221 Fireball and a .256 Winchester Magnum both have a lot of muzzle blast!

[GONRA]

GONRA sez - These days, (as ya’ll no) one can NUMERICALY calculate how most anything verks
with the nearly unlimited computer power out there…..

In this case, geometry is “axisymmetric” (round) greatly simplifying it all.
“EZ geometry….”
“boundry condtions aren’t THAT bad”…..
“etc.”

Am decades behind on this stuff, but am sure there is lottsa canned computer stuff
(computational fluid dynamics) (?) available to do the numbercrunchin’.

HARD PART: “develop a material model for LUBE …”

Have Pun Fellas! !!