40-45 max...unless your very confident or are made by cyberdyne systems and are a terminator...who knows....seriously, its all about, YOU...if your a good shot, using todays technology and use the right ammo...go for it...i used to use a telephone book at varying distances to see what energy was left in the pellet, bit heath robinson..but, worked....alternatively use a chrono (like an F1) and shoot are varying distances to get an accurate reading of the energy in those pellets...finally, if your going for distance, remember the wind does play a part in the accuracy...the longer the pellet has left the barrel the more outside forces will affect its path...practice till your confident and competent your going to get a clean and humane kill, G