You wouldn't be able to chamber a 460 round in a 454 cylinder since the 460s are almost a half inch longer.
Here's a pic. 45 Colt on the left, then 454, then 460.
I have both a 454 and a 460. The 454 is really more than most people would ever need. If your goal is long range target shooting, large animal hunting (elk, moose, grizzlies, or dangerous game in Africa, then a 460 may be what your looking for. But even then, a 454 would most likely do the job. The 460 is a hoot to shoot though.
