there is a couple places that will machine your cylinder to take moon clips so you can use all 454 ,45lc,45acp
Also, Moon clips for 45 ACP would leave too great of a jump to the forcing cone.
It seems to me that if you're worried about some sort of situation where you aren't going to be able to resupply (except for scavenging) that you should just buy common guns in common calibers (i.e. glocks, AR-15s, 1911s, etc) and just stock pile yourself more ammo than you would ever think you would need. I mean, if you have a G19, a ton of magazines, 10-20k rounds of 9mm and a lot of spare parts/back up guns, are you ever really going to run out? Don't you think you might die or run out of food before that happens if civilization collapses? I don't think anyone is really going to burn through that much ammunition (aside from hunting, but I would assume you're using a different firearm for that) without getting in a situation where they're hurt or killed before expending tens of thousands of rounds.Also I would think in general you'd be better off stock piling a ton of food and a reasonable amount of firearms/ammo/accessories than going to ridiculous levels.On a lark I hit up http://www.gun-deals.com and found the cheapest brass cased ammo I could find which was shown as ~22 cents a round shipped to my zip code in Boise, if you shelled out 2,220$ you could stack up 10k rounds of 9mm in your closet.
...I am thinking of SHTF scenario...
I am thinking of SHTF scenario, or if I end up with a bucket full of 45. ACP falling at my feet.