If u r any kind of a shot size does'nt really matter . I've used 30-06 , 7mm , 308 and 243 . I must say the 243 is my favorite , one shot in the neck , all done . Simple cheap and a joy to shoot for all . My wife shot her first buck this year with a savage model 11 243 , one shot in the neck , folded him where he stood ! Most important , be a sportsman and take only good quality shots .