Maybe this will answer your question. I don't shoot them but Len has tried several brands over the past couple years. He has a set up with a lot of "UMP" behind it ( 78 or 80 foot pounds). All he's shot with mechanicals had entry holes as large as any shot with my Thunderheads. He had one deer last year that was "danger close", angled toward and below him. He picked a spot right behind the front shoulder. The arrow hit the deers ear on the way by. The mechanical put a picture perfect 3 bladed X through the thin part of the ear before drilling through the lungs. This was a small deer and a thin ear, but it opened fully going by.