Years ago I played with the old .451 Detonics Magnum cartridge. It was a hassle having to rechamber barrels for it. So, what I did was cut down all my .451 Detonics brass to .45 ACP length, to create some ".45 Super" cases [ long before they were commercially available ]. I loaded these ".45 Supers" mostly with 230 Gr Hornady FP bullets. I found that with HEAVY bullets, loading to an OAL that fit inside a magazine, limited any theoretical advantage of the longer .451 D Mag case. With .45 Super cases, I got very close to .451 Detonics ballistics. So I standardized on .45 Super instead of .451 D Mag.

Originally, I did most of my shooting with a SS 6" coned Heavy barrel, which was not even ramped. Case life was good, but it was obvious that HOT loads did bulge into the unsupported area. Eventually I went to a SS 6" ramped barrel from Clark, and I hung a comp on it.

If you are going to shoot .45 Super, it is a very good idea to start with a short chambered RAMPED barrel, and after fitting the barrel to the slide and frame, cut the chamber precisely to fit the brass. Most .45 ACP barrels have very deep chambers, and these over long chambers will allow the brass to jump backwards quite a bit before contacting the breech face. This is NOT good for brass life.

Also, a Colt Govt model pistol MUST be set up properly before firing .45 SUPER loads in it. Firing pin, extractor, and of course recoil springs, have to be tuned correctly for safe and reliable functioning with these powerful loads. Trigger jobs that are safe with standard .45 ACP loads, may NOT be safe with the faster recoiling, more powerful loads.

PS: Invest in Pachmayer rubber grips - the soft rubber cuts down on the recoil, and if you ever blow out a case, you won't be picking splinters out of your hands from the wood grips.