


I thought someone topped that a few years ago, 50BMG case necked down to a .17 HMR bullet.
.22 LMSSSS (Long Magnum Super Sonic Special Shit). Energy varies proportionally to the square of the velocity, so at 4,600 ft/sec with a 50 grain bullet that's 2,350 ft-lbs of energy. For comparison purposes, a typical 62 grain AR-15 bullet traveling at 3,200 ft/sec possesses 1,410 ft-lbs of energy. So that abortion of an experimental round has about 66% more energy at the muzzle than the AR round. Barrel life should be 250 rounds tops at that velocity.
Armor piercing much there?

That shoulder is going to cause one hell of a pressure spike.