Originally Posted by
Junior1942
At 2,000 fps my 9.5" twist Yugo is spinning a bullet 151,578 rpms. Not many cast bullets would make 100 yds at that rate without coming apart.
My 1700 fps load turns 128,842 rpms, which is borderline disintergration with my alloy (ac/ww). When you notice groups spreading out and strange little commas on the bullet holes, back down the powder charge. The little commas are the bullets coming apart between the lube grooves.
Note: Thanks to Newton, a bullet going 2,000 fps at the muzzle is still going ~2,000 fps at the target in spite of its decreased velocity.