A good round would be a 30-40 Ackley imr. I have a 30-30 Ackley double i built about 20 years ago for deer in Pa. I have killed to many to remember with this little gun, 21 in bbls 5.6 lbs. Every one likes to use it, i use Hornady 150 gr at 2475 fps. I build most of my doubles on staight cases or imr. case. It reduces the rearward thrust of the case about 30% in a dry oil free chamber. Rich