[Seraph]

Mr. Miles is correct, but I'll say I've fired a good bit of hot ammunition - Double Tap, +P and .45 Super - through my 1911's with "unsupported" chambers, and have seen zero case bulge. .45 ACP is such relatively low pressure stuff, that even the very hot iterations seem not to have pressure enough to blow out the cartridge case. I wouldn't worry about it a bit. As for the recoil spring setup on the Champion, the easiest swap I've read about was the use of a Kimber Pro series guide rod and 22lb spring, with the stock Champion spring plug. Thus far, my GI Champ still retains her stock setup, which seems to keep on performing flawlessly for about 600 rds now. When I hit 1000 rnds, I might try the Kimber part.