Did the deer stand behind the tree all day............... I personally would not use either a .40 S&W or .45 GAP on a deer........... . Neither would be my choice, a .357 mag, .41 mag, .44 mag, .454 casull, .460 S&W mag, .480 ruger, .500 mag, possibly one of Seismics .50 GI (or any of those...