Think you will find less meat damage with a slow 45/70, which is farther from overbore than an '06. Even using copper bullets, if you use the weight range for the game, and caliber selected, you will see meat damage, especially at the close ranges the OP wants to shoot at. Better to use the 45/70 cookie cutter thru the deer, then a small bore high velocity round that relies on hydroshock to work. Now if you want a buffalo gun, I have a 375H&H, but you will find minimal meat damage on deer with it as well.