ORIGINAL: HighDesertWolf
imo even 1200 fps is a bit fast, the faster ya push them the more lead they leave behind. I generally dont like to push lead faster then about 1000 fps if i was gonna push them any faster Id deffinately use gas checks.
What kind of lead bullets are you talking about? Made of certain alloys and used with the proper lubricant for the job, cast bullets can be shot at velocities over 2700 FPS with good accuracy and with NO LEADING whatsoever.
I use the 265-grain, .452" Cast Perfomance gascheck bullet in my .454 Casull with 28 grains of Alliant 2400 with a MV of 1550 FPS. This is a mild load. I shoot the RCBS .417" 350-grain gascheck from my .416 Rigby at 2100 FPS. It is a greatdeer and black-bear load.
For about all anyone needs to know about using cast bullets, I recommend one read Veral Smith's book, "JACKETED PERFORMANCE WITH CAST BULLETS".
As far as terminal performance is concerned, a too-hard alloy, likeLinotype, can indeed shatter on impact! I use a heat-treatable alloy for hunting bullets, and harden JUST THE BASE portion by heating up the bullets while they are standing in a shallow container like a jar lid. Then when the bullets are up to the correct temperature for that alloy, I remove them from the oven and immediately immerse the base sections up to about the top rotating band in cold water. This leaves the nose soft enough to not shatter, but it will expand on impact, and the base is tough enough to take the rifling without stripping at velocities up to 2300 FPS (Lyman 457122HP in the .45/70).
LTB (Veral Smith) used to make a "double mould" arrangement so he could make the bullet shanks from a hard alloy and the noses from a soft one. But if the bullet is long enough, it is possible to harden only the portion that is engaged by the rifling.....