your limited to what ever range that you with your gun can place your shots 100% of the time on the deers vitals, Ive shot deer at about 170-180 yards with my 1894 marlin in 44 mag,( 2.5 x leopold scope) the 300 grain cast ,gascheck bullet zipped clean throught, the deer dropped!
Ive shot deer with a 44 S&W at about 120 yards with the same ammo, results were very similar, your ability to place the shot correctly and the bullet choice are the more important factors.
practice on a 6" paper plate from field possitions,with your gun and if you can,t keep every shot on the plate your exceeding your effective hunting range and should not fire at game beyond that range