Just curious, I read a lot about reloading my 44 magnum, I came across some 444marlin data by people claiming to shoot 300 grain cast projectiles near 2000fps. Even with gaschecks would that be possible? Wouldn't the lead just melt and come out as lead splatter?
444 marlin
- Thread starter bandit86
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Why would the lead melt?
People shoot cast bullets out of .50 BMG's.
People shoot cast bullets at 50,000+ psi.
People shoot cast bullets at 2500+ fps.
If the pressure is high enough to liquefy lead then it would crush a jacketed bullet and liquefy the lead core.
If the temperature is high enough to melt lead then the lead core in a jacketed bullet would melt.
If you put too much pressure behind a bare lead cast bullet the gas can cut up the rifling and deform the bullet causing it to lose stability or tumble (maybe break up but not splatter or melt.) The old myth about the base of a cast bullet melting from the pressure and temperature of the gas has been proven wrong. With a gas check the only real restricting factor is lead-steel friction between the barrel and bullet. Using the proper bullet lube for the given velocity solves that problem. I believe there is lube out there specifically designed for 3000+ fps with cast bullets.
The maximum velocity for pure naked lead is around 1700fps. If you go higher you can just use a harder alloy of lead. If you push lead or really any metal too fast it will deform with the air resistance. Maximum cast bullet performance is usually given in muzzle velocity, not muzzle energy. How heavy the bullet is doesn't have much effect on how fast it can be pushed (within the limits of the given cartridge.)
People shoot cast bullets out of .50 BMG's.
People shoot cast bullets at 50,000+ psi.
People shoot cast bullets at 2500+ fps.
If the pressure is high enough to liquefy lead then it would crush a jacketed bullet and liquefy the lead core.
If the temperature is high enough to melt lead then the lead core in a jacketed bullet would melt.
If you put too much pressure behind a bare lead cast bullet the gas can cut up the rifling and deform the bullet causing it to lose stability or tumble (maybe break up but not splatter or melt.) The old myth about the base of a cast bullet melting from the pressure and temperature of the gas has been proven wrong. With a gas check the only real restricting factor is lead-steel friction between the barrel and bullet. Using the proper bullet lube for the given velocity solves that problem. I believe there is lube out there specifically designed for 3000+ fps with cast bullets.
The maximum velocity for pure naked lead is around 1700fps. If you go higher you can just use a harder alloy of lead. If you push lead or really any metal too fast it will deform with the air resistance. Maximum cast bullet performance is usually given in muzzle velocity, not muzzle energy. How heavy the bullet is doesn't have much effect on how fast it can be pushed (within the limits of the given cartridge.)
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Cast the lead harder.
Lead fouling in a barrel can be caused by several factors.
-undersized bullet
-rough or uneven surface inside the barrel
-no lube or wrong lube for given velocity
-excessive pressure without a gas check (past about 1700fps you want a gas check but it is different from barrel to barrel)
-other stuff I'm forgetting
Generally you want to use a cast bullet that is at least 0.001" over bore diameter (you have to slug your bore) but I have used bullets up to 0.005" over without issue. You have to use an appropriate lube for the velocities you are pushing the bullets to, gas check if necessary, and use a hard enough lead alloy for your purposes.
The hardness of lead alloy can be controlled through several means but some are only temporary. Pure lead can be water dropped (quenched) to harden it but it will soften in a matter of hours. Lead-tin alloy is harder but can be made even harder with water dropping. The lead-tin alloy will soften back to it's non-quenched hardness (which is still harder than pure lead) after a few weeks though. Another significant advantage of tin in the alloy is it allows the molten metal to flow better so you get fewer bad bullets (gaps, bubbles, etc.) when casting. Lead-antimony or lead-tin-antimony alloy is even harder but has the same effect of quenching and softening again over time. The hardest lead alloys are lead-tin-antimony-arsenic; it again will soften over time if quenched but the point it will soften to is still quite hard.
People push gas checked, hard alloy, cast bullets with the proper lube to 2500fps and beyond without leading or significant fouling. It's far more complex with more variables than shooting jacketed bullets but most people who shoot cast tend to be tinkerers anyway.
