It is a +P++ 45 ACP, and requires special "45 Super" brass (thicker at the web area). You can get 100-150 fps more than +P 45 ACP, in all bullet weights. Maximum pressure is about 28.000 psi (double than normal 45 ACP, but still not too much). Apparently all it requires is a stronger recoil and firing pin springs, maybe a stronger mag spring, and an all steel 1911 in good condition to convert it from 45 ACP to 45 Super. "45 Supèr" is registered by Ace Custom, and this, together with it having the same external dimentions as the 45 ACP caused SAAMI and commercial manufacturers of guns/ammo to not embrace this fine cartridge. You can read a very good article on it in: www.realguns.com . Hope this helps.