Blain,
See my comments to Daryl above. I have had some luck with going from the jacketed bullets that were used during regulation to hard cast heavier bullets, but, In most case you need to change the powder charge some and maybe even go to a different powder. The secret in my humble opinion, is to try and get the speed close to what it was regged with, without getting crazy on extra recoil as both speed variations and recoil changes will both throw it off somewhat. The other thing is what are you willing to accept as far as accuracy with the different bullets? These doubles were origanaly made up and primarily intended to be used at fairly close ranges, I would say 30 to 50 yards or so, with an occasional shot at 75 to 100 yards. If the gun will regualte and shoot grapefruit sized , two barrel groups at those ranges, then I feel that should be good enough to hunt deer with and at whatever range you can shoot those groups. Smaller groups are always better but not vital to hunt with. Bob H.