I would agree with Bambi on this. The 2 1/2 inch groups are good enough to kill a deer, just make sure you are putting it snug to the crease and let it go. At that distance anything on to the shoulder should penetrate very well and anything back a little will still be well within the boiler room.
Along the lines of this, last year my dad was all excited to bowhunt with my buddy and I. Well he pulled out his bow and found out that it was harder to pull than he remembered. After adjusting the draw weight down he said he was good to go. Well, we saw him shoot and boy did he struggle with drawing and shooting accurately. Felt bad for him because he was the one who taught me and boy was he a great shot. Offered to bring down our crossbow for him to use this year and he graciously accepted. Kind of think of it as an equalizer for him I hope. If I had the money I surely would be buying him one of his own.