Good 45 colt brass (starline, federal, win, froniter, rem) can take a steady diet of 300gr @1200 fps with good case life (in Ruger/FA revolvers ONLY, of course). A load like this is as powerful as a fullhouse 44 mag load and kicks just as much as well. I believe Corbon makes some even snottier (factory) loads they refer to as 45 colt "magnum" loads. I've owned a number of Ruger 45s and am about to buy another one (5-1/2" BH with the ACP cylinder).

For full power loads, H110/W296, 2400, and AA#9 are very good powders. For reduced loads I like Unique. Anyway, good luck.

I might also mention here that the 45 Colt (long) was developed in 1873, the origional load was a 255GR LRN bullet loaded with 40 grains of blasck powder to a MV of 810 FPS, from a 7 1/2 inch barrel, it killed a lot of things other than indians.