cayugad I use a .50 cal CVA timberwolf sidelock with 1:32 twist. I have taken 8 elk here in Az 5 cows 3 bulls using this gun. I am shooting 100 grains of pyrodex and a 245 grain ballet from bufflo bullet company. None of the elk have gone more than 30 yards after being hit. and the longest shot being right at 100 yards ( I had a scope on the gun at that time) but like you said a .54 has a little more punch. I also sent an email to colo game and fish to see if the powerbelts are allowed. Powerbelt advertise that they are but I just want to make sure since I will be moving up there in oct. after our elk hunt here in Az sept 26. good luck