My dad shot a huge P&Y Canada Moose in Northern Minnesota back in 1987. He was pulling 80lbs back shooting a Howard Hill longbow and he drilled the moose perfect right behind the shoulder at 15 yards. The problem was that he hit the rib bone dead center which caused him to loose some penetration on his arrow. He still got both lungs but barely, the moose lived for 6 hours. My dads set up was 2216 arrows with 175 grain 2 blade cut on contact broad heads. His arrow weighed around 600 grains which was a good arrow weight for moose hunting, its also his normal set up anyway. If he wouldn't of hit the rib bone square he would of had much more penetration. If he would of had to light of a set up he figures he never would of got that moose. Make sure your set up is what it should be. If I was you I'd be shooting an arrow set up that is a little on the heavy side being these moose have some big ribs.