Molten Lead & Jacket Separation

Hello, I just joined in hopes of reviving a thread that was started on 1 Sep 2021 concerning copper jacket spinning around lead core. There were some interesting theories proposed as well as disagreement on whether or not lead core becomes molten after firing. I can provide photos to prove molten lead and show the results after bullet impact. I wish to set spark to an interesting discussion on molten lead and external ballistics.

You start. What are your thoughts about it?

Show photos

Is your theory that the heat of burning powder melts the core? Or the friction from the barrel? I kind of doubt my Sierras are molten when they reach the backstop, as they mushroom the way you would expect solid lead to do.

Put me on the "I doubt it" list.

If burning powder or barrel friction were to melt the core, I would think that would be visible on high speed camera as a bullet exits the barrel. I have not noticed that when viewing the various footages out there. I also have not been looking for it, so maybe I just missed it. I would also think the exit temperature of a bullet could be ascertained. Lead has a known melt point, and should be easy to compare to see if its possible.

I remember that old thread. If it were true the old Nosler Partition bullets would have left lead in the barrel and never worked as described. They had exposed lead at the rear of the bullet.

Welcome from Colorado. I'm on the list of none believers too.

Do the chemical engineering calculations of melting non-pure lead. I'm sure the lead composite is NOT melting to any significance while inside the jacket in the barrel or in flight. Upon impact the bullet energy has to be transfered as heat to now unprotected lead that no longer is shielded by the copper jacket. So, at impact on steel, you may see some melting and some simple smearing like pencil lead/graphite, but not before it impacts the steel.

Lead tipped bullets can have the exposed lead melt while in flight, something I can prove by targets that show tiny "comets" or curlie-cues of lead on the paper. This takes a velocity that's pretty high, something close to 4,000 fps (possibly less, I don't remember the exact number).

As to core lead melting, I would guess that little more than a few molecules of thickness of lead would become liquid *if the jacket were significantly spinning around the core.* This is something I am not aware of although it certainly could be possible. However, considering the time of flight and the fact that the core is accelerating at the same speed as the jacket, any difference in temps between the jacket & core shouldn't be that great. Enough to cause melting? Beats me! Off hand, I would more easily accept some jacket slipping around the core while in flight, which would not involve any melting of lead at all. Lead is a fairly decent lube when under pressure but enough to allow the jacket to actually spin? Again, I have no idea! Add in that there are so many other factors, bullet diameter, launch speed, lead composition, lead/copper pressure during manufacture.... it becomes a huge, and probably expensive, problem to solve!
Cheers,
crkckr

I am patiently waiting for the op to disclose some solid info on this subject. I can only say that lead melts at 621.5 degrees F and most copper melts at 1,984.6 degrees F. It seems to me after 40 plus years of slinging lead that maybe the jackets of certain bullets with a very fast twist at high velocity is spinning the copper jacket from the lead core and not melting. It seems all lead bullets would be affected if melting is the issue. I am only making a non scientific red neck guess so be easy on me, welcome to the site DMM9623. Jason