If you put your scopes crosshairs directly in the middle of his chest the bullet has to bypass his vitals to hit his guts=dead deer. I have shot several with a 223 with a 55 grain bullet and it drops them everytime, bigger guns make more of a mess so I try to avoid that shot because I no longer use my 223 for deer (not legal in VA). But I can tell you if I have a trophy buck standing in front of me facing me he is going to get a 139 Grain pill from my 7X57 right into the chest!