Yep!! Why rechamber, when the 45-70 will do everything needed? Believe me, much fewer headaches, re: case capacity, etc., and it will do everything on this continent you need. OK- my 450 3 1/4 BPE, uses 3/4" of filler to get reliable burn, the 500 2 1/2 is OK with 1/2" filler. If you want a bigger case, that's fine, but understand you won't gain anything but a big case, with modern powders. Black is another story, but with a 450 3 1/4 it can boot the heck out of you!

+1 with Marrakai, a longer chamber may actually be a detriment in the reality department. Case expense/ availability, actual performance gain ( loss? ), etc.

My 2 cents worth--- Doug