using something that he calls the ".45 Professional", it's a cut down 284 Winchest case, using 230 gr .45 ACP bullets,at 2900 fps. 4300 ft lbs. I'd never load it THAT hot, but 3000 ft lbs might make for a good "bear gun". You might be able to get 270 gr,solid bronze slugs going 2250 fps, and then you could take ELEPHANT with a CAR-15. Jack OConnor's wife took a tusker with a 3000 ft lbs 30-06,with one shot to the ear hole. Kilamajaro Bell took hundres of themwith 2400ft lb 7x57 Mauser and 6.5 loads. Several guys have taken elephant with big pistols,even. The solid bronze bullets, tho,in an autorifle, would let you stop a charge by YOURSELF,instead of depending upon your guide and his heavy rifle.