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Discussion Starter · #1 ·
Saw this on a Bulls Eye board. Had always wondered myself. Soooo, I pasted it here. Read it for the first time seconds ago - comments?

://www.lasc.us/TaylorLeadingDefined.htm
Reprinted With Permission Of Jim Taylor and Leverguns.com
Leading Defined
SNIP
The burning propellant will not melt the base of a lead bullet! There
is simply too much physical mass to heat to the melting point of lead
(about 600-700F) in the short time a bullet is exposed to the
propellant gas to bring it to it's melting point! If you want proof,
examine wads used in shotguns or black powder cartridge loads after
firing. They may show slight darkening, but won't be consumed in
flames either! If the burning powder won't melt the plastic or burn
up the cardboard, why would it melt a bullet base? The answer is, it
can't.

Some years ago my Dad and I ran tests to see if heat could
actually melt the bullet bases. We used .357 and .44 Magnums as the
test vehicles. To the bullet bases we glued flash paper, the kind
magicians use. No matter which powder we used, we were never able to
ignite the flash paper. We also put low temperature wax on the bases
of the bullets and again were unable to get any wax to melt. As was
said already, if you can't melt the wax you sure won't melt lead.
 

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I am no metallurgist but isn't the deposition of the lead or copper cladding have more to do with galling or the wiping action and the friction between the laminar surfaces of the different metals. Or something like that ??

T.D.C.
 

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Discussion Starter · #3 ·
I agree with you. It was just one of the Q's that had been rattling around in my mind for a long spell. Never could figure out why lead bullets with no gas check wouldn't just leave a puddle up the bore.
 

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If you look at the base of fired full matel jacket bullets from the 308 and 30-06, that have been recovered, you will see tool marks, and no melting - if the can't melt at 55,000 psi, then they aren't gonna melt.



.
 

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Read an article a long while ago

and I think it was in "Guns & Ammo" titled "Ablation and the Bullet" Pretty thorough testing with the same conclusion--no melting of the bullet.
Bob
 

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I don't claim to be a metallurgist or very intelligent, I'm just a country plinker. I have a 30/338 mag that I was having issues with the 190 Gr Sierra Match bullets so I called the techs at Sierra. After talking with the guy for about 30 minutes he asked if the target showed any signs of a smoke trail above the bullet hole like the bullet had set the paper on fire and then it went out. Well, yes, there was a black whisp of something above every hole. Per the Sierra tech, the bullet core was still molten and the smokey hole was evidence that the molten core hadn't stablized yet. From what I gathered in talking with him, a combination of 60,000+lbs of pressure and the heat from a magnum case of powder will cause some bullet/cartridge combinations to have the core of the bullet go to liquid. I slowed the bullet down and the smokey trail stopped. The Remington 40X still likes the max loads and I still use that load for longer ranges. So I would say yes it's possible to melt a lead bullet in a barrel but not with the puny 44 mag or any normal pistol cartridge.
FWIW, try 60.0 grs of 760 powder with a 110 Speer varminter out of a 3006. It won't make it to the target at 50 yds. It does leave a smokey trail starting at 20 yds and runs out around 40 yds. On second thought, don't try it, take my word for it. The bullet burns up at those speeds and is not built for that much velocity.....but it is fun to give to folks that don't know any better and watch their face when they can't hit the paper at 50 yds with my gun.
 

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I had a .228 Ackley Magnum, one of the first hotrods fro ole' P.O. I did some research and learned that early on there was a problem wit hthe bullet blowing up from the rotational forces. The early clad bullets were not up to the task. Sisk bullets from Texas deveolped a solid copper alloy bullet in a hollow point that held together. This was probably in the mid to late 50's. They were more like what we see today in match bullets.
I would like to see more about the molten core theory if there is a link to access. Sounds interesting.
 

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Very interesting. Back in my pistol days, I can remember many a comment by various gun writers on the melting of the lead at the base of a bullet. Gas checks were often touted as being a gurad against the bullet's base being melted off by the powder charge.

After the space shuttle disaster, there was a hearing among all the experts to determine what went wrong with the boosters. Arguements went on among the group for hours about the design specs of the gaskets between the sections of the rocket boosters; what they would and would not do, yada, yada, yada... All but one was in the fray- and independant scientist (I don't remember his name) sat alone at the table, stirring his ice water with his finger...

"Gentlemen!" the lone scientist exclaimed, bringing the hub-bub to a sudden halt and all faces turned to him and eyes looking at the ice water in his glass, and some piece of black stuff floating among the ice cubes.
The old scientist continued: "(In effect) All this talk about what the gasket material will or won't do at freezing temperatures can be solved by a simple experiment. Here I have a piece of the gasket material in a glass of ice water. I think we could agree that the temperature of the water, due to the melting ice is pretty close to freezing. (The group nodded in agreement.)

The old gentleman took the piece of gasket from the water and pressed his fingernail into the material, clearly leaving the imprint of his fingernail in the material which had not sprung back as some expected it would. "Well, it seems obvious that in spite of what it is supposed to do at freezing temperatures, obviously it does not rebound. Draw your own conclusions."

Once again, it amazing what can be shown by actually doing a experiment, as opposed to taking as gospel the words of "experts".

Interesting post.

P.
 

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Melting lead

In my young and foolish days (okay, a couple years ago...) I decided to load up some 45 grain Hornet bullets in my 220 Swift and push them as hard as I could just to see what happened....(my mentality is showing up here huh?) And what I found was interesting! Did ya ever hear of comet tailing? At 100 yards you could plainly see little comma shaped halos around the bullet holes in the white paper. I've heard the term many times but never really researched it to see why it does that. But in any event is certainly looks like molten lead spraying off the nose of the bullet. If I remember correctly, at 50 yards it was worse.

I agree with Don on bullet erosion too, I've need it happen in full house loads where the back of the bullet looked like someone took a minature torch to it. Of course, that's why they make gas checks and bullet molds to make bullets that accomidate gas checks.

Maybe someone here can expand on comet tailing? Not to be confused with tail gating of course!
 

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One thing about melting cores though... If the core of a jacketed bullet melted while traveling through the barrel, the liquid would not be spinning as fast as the jacket after exiting the barrel (the ultimate "stripped core"). Simply because of the higher moment of inertia for the lead vs. the solid copper jacket. Stripped cores are known to cause slow and variable rates of spin. A bullet with a melted core would have a good chance of going through the target sideways. Accuracy would be shot to heck, at least.

- DAA
 

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I don't claim to be a metallurgist or very intelligent, I'm just a country plinker. I have a 30/338 mag that I was having issues with the 190 Gr Sierra Match bullets so I called the techs at Sierra.
Hold on fellows. Lets confuse things with some real science.

Like others, I have had targets with spinning comet shaped tails around the bullet hole... and I have had bullets leave "vapor trails" as they flew down range.

But here's some things to consider...

Larry speaks to the 30/338 Mag. Now... if that's the 30 cal on the .338 Lapua case, or the .338 Ultra Mag case, then it's certainly in the "beast" category when it comes to powder consumption department. At 90 to 92 grains of powder, both are about 10 to 12 grains larger than the 300 Win Mag, which is no slouch in it's own right.

The bullet time IN THE BARREL, for a high velocity bullet is 1 to 1.5 thousandth of a second (4000fps = 2000fps average speed in barrel, divided by 2feet = 1/1000 of a second).

Now, the temperature of an oxy-hydrogen torch is 5000+ degrees.

You can pass the flame of an Oxy-hydrogen torch over a bullet for a few thousandths of a second (just sweep it across), and then you can pick it up in your fingers... cuz it ain't gonna be hot.

That's because of "Thermal conductivity". The copper/zink jacket cannot carry the heat fast enough to get the bullet hot. The 5000+ degrees for two thousandths of a second will not penetrate to the lead...the melting point of copper in 1950 F, and the torch won't even melt (or even frost) the jacket either.

And if it was a case of melting... then the heaver bullets would show "melting" long before the light bullets, because the heaver bullets are in the barrel (ie exposed to the heat) longer than the light bullets.

But lets walk away from Larry's 30/338 (sorry Larry) and go down to the diminutive little .223 - a mere pip squeak among giants.

We can see the SAME EFFECTS with the .223 and a 50 grain Sierra Blitz (soft point) in an AR-15, with a 9" twist. No 90+ grains of powder here... the powder charge is in the 26-28 grain arena.

The bullet in this case, will leave a vapor trail, and probably disappear in a puff of smoke.

And low and behold, if we change the Blitz for the Sierra 50 grain soft point (the exactly same bullet, with a jacket a few thou thicker), nothing happens. No "melting" no vapor trails, and no comas on the target. But according to the theories, this one should "melt" too.

This is because the vapor trails and smoke and comas are caused by the jacket splitting along a rifling edge... because of excessive centrifugical force splitting the jacket. Then the lead comes spilling out under the awesome pressure of spinning some 250,000 rpm.

In all of these cases, if you go to a slower twist, the problem just disappears.

So it can't be caused by melting...it's caused by spinning the bullet faster than the jacket can hold it together.

.
 

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I'm seeing the same thing in a 5/35 SMc that I'm testing. No problems with 39/40-gr Sierra or Hornadys at up to 4100 fps. Great accuracy. But then I drop to the 32-grainers, things go to pot. The Sierras would be more accurate, if they'd hold together, but from one to four out of five don't. Some hit the target sideways, some leave comet tails, and some just never make it to the 100-yard paper. I have to back the Biltzking lightweights down from 4300 fps all the way to 3900 before they stay intact.

The lightweight Hornadys stay together, but aren't as accurate (or, they're MORE accurate because at least they GET there!).

I'm thinking of giving the 32 Blitzkings a Fastex treatment to see if the reduced friction reduces the rifling stress lines enough to help.
 

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Rocky, those SMc designs caught my attention a while back... have you done much testing yet? Are you going to do a whole write up here when you are done?

Thanks
Mark

p.s. I am no scientist, but I thought vapor trails were just that. Water vaper being compressed and moved by the passing projectile.
 

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Core stripping...

If the core of a jacketed bullet melted while traveling through the barrel, the liquid would not be spinning as fast as the jacket after exiting the barrel (the ultimate "stripped core"). Simply because of the higher moment of inertia for the lead vs. the solid copper jacket. Stripped cores are known to cause slow and variable rates of spin. A bullet with a melted core would have a good chance of going through the target sideways. Accuracy would be shot to heck, at least.

- DAA
Core stripping is vering off topic, but often I've seen posts here where someone is experiencing keyholing with a light bullet and a twist rate much higher than adequit for stabilization of that particular bullet. Core stripping is one of the things that always comes to my mind, followed by a bore that may be choked with fouling so that the bullet is not being spun properly.

But, as far as melting the lead that is exposed to the flame front, I have many Nosler Partition bullets recovered from my backstop, and I noticed specifically that NONE of them show any sign of melting, at least to the naked eye.

Ah...SO much "information" out there is not supported in fact...Something new!:rolleyes:

Love your posts, buddy.

P.
 

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Markbo, I've been working with the little cuss for two years now - way too long. But I'm hampered by my range closing for the winter (and my unwillingness to shoot at another local one), plus a long series of difficulties trying to get my Pressure Trace system to work correctly. The problem, I hasten to add, was NOT with the Pressure Trace but with a series of strain gauges, my laptop and other frustrating factors. The RSI people and equipment have been superb.

I will write it up, if I ever get satisfied that I understand what the heck is going on with both the bullet failures and the pressure data.

Everyone who has helped (Sierra, Hornady, RSI, Savage and the developers of the SMc line) have been superb and very understanding, BTW. It's just me who is flogging around.
 

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Discussion Starter · #19 ·
Just now have remembered and visualized the countless 45 round nosed jacketed bullets recovered from a backstop with the exposed lead bottoms that showed no visible sign of lead loss. Melted them down for "new" H&G #68bb swc's.
 

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Lead 7.7 Jap deposits in gas piston

Some 30 years ago, I made the mistake of trying to shoot lead cast .311 gas checked bullets in my Type 99 Jap LMG. No problem in the old barrel. Big proglem in the gas piston tube. Erosion of the lead built up in the gas piston tube and caused the gas piston to bind and fracture.

The eroded lead looked 'frosty' as it built up. No evidence of melting, even at 900 rpm. Lucky for me the machine shop instructor at Griffin Tech was able to repair the damage. Learned a lesson. No lead in MG's.

Still have some of the slugs. Just haven't found them when I was casting 16 oz bottom lead for Grouper.

Old Doug
 
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