I'll kick in my pitch for the .454 Casull also. I have one in 12" for my Encore, it shoots as well as my big rifles for accuracy, plus I can load anything from 7 gr. of Unique and a 250 gr. bullet for zero recoil, one hole groups at 25 yds, up to 27 gr. H110 and a 320 gr. bullet that shoots a 1" groups at 100 yds and I can hit oil bottles at 200 yds. with this load with a good rest. I killed two whitetails with it this fall, my first handgun kills, and I was very impressed. I've done a lot of load work up with H110, Unique, and AA#9, and I have several different mid-range loads, a couple great plinking loads, and some elephant loads. The factory barrel shoots all of them well enough for me, and I reject the load if it doesn't shoot 1" at 50 yds. I'm using mostly cast bullets from 250 gr. up to 370 gr, with the right powder charge all of them shoot 1" or better at 50 yds. The only jacketed bullet I've used is the Hornady XTP-MAG, and it shoots well with a max load of H110. Hope this convinces you. BTW, you don't need to buy extra .45 Colt brass for plinking loads, the length difference is only .10", and you have to reset dies for loading the .45 Colt, plus buy different primers. It's not worth it in my opinion to get the .45 Colt brass, just load down your .454 Casull brass, I'm on 10+ loadings with some of my brass and it's still in good shape.
Selmer