KDM, I have a 50 alaskan BFR revolver that has a long enough cylinder to handle these. I shoot both Buffalo Bore factory loads out of it now. With a 9 1/2" barrel it gets 1708 ft/sec with 525 grain bullets, and 1928 ft/sec with the 450 grain bullets. Not bad out of a 72 oz revolver. Mic McPherson should be getting 450 and 500 grain bullets from alaska bullet works this week to test my 510 K.E. Marlin conversion Then to robar for np3 finish and finally to me.I can't wait to shoot it! It has 23" bl, wt. 10 lbs,holds 7 rounds in the tube.