If you're looking for the ultimate in "stopper" rifles, then you need a custom bolt-action gun by A-Square, Inc., in .557 T-Rex (Tyrannosaurus Rex). The rifle fires a .557-inch diameter, 750-grain bullet at 2,450 feet per second from a 13.8-pound rifle. Muzzle energy is a whopping 11,000 foot-pounds. The rifle is designed to be the big game hunter's ultimate last-ditch to stop a charging rhino, elephant, or cape buffalo.
Unfortunately, the recoil level is off the scale -- about like being hit on the shoulder by a 350-pound linebacker swinging a 20 pound sledgehammer. This rifle is not ported nor compensated. The muzzle blast from a 26-inch barrel is huge.
One shot is guaranteed to give you a FLINCH where you never had one before. Ouch, ouch, ouch!