Good points above. 50#'s is more than enough to get your deer. My son has taken deer at 42#'s when he started out to 20yrds. I know what you mean shooting at 40yrds. I shoot 60lbs and It takes time to get the arrow there. Isn't that telling you something? I know others will disagree with me but 40yds is a long way out there and most guys shouldn't take the shot. I have been shooting since 1996, am comfortable target shooting at 40 and I wouldn't take a shot that long at a deer. Believe me there is no worse feeling than crippling one and not finding it. Think about the size of the kill zone, go rent a DVD by Drury Bro's or The Trueth and watch a few kills in slow motion. Watch the reaction and amount movement of the deer before the arrow gets there at a 20yard shot. Then think about the same thing at 40. Most of the deer I have shot have been 20 yards and under. Longest shot 4 me is 28yrds. I have not lost one yet.