Just last saturday afternoon I shot a 9 pt. buck with a Rocket Sidewinder(1.5" cut) at 18 yards quartering away from 22 ft up. The arrow buried to the fletch. When I found the deer 60 yards away it had a huge entrance & exit wound and the head was actually stuck in the far side leg bone. Now I am only shooting 60 lbs with a 370 grain arrow @ 260 fps which equates to about 54 ft lbs of KE. My bow was tuned to shoot bullet holes and in my opinion there was no problem with penetration, even on the quartering away shot. The key I think is what everyone says, have a well tuned bow and good shot placement.