It's all in the conetic energy .less than 50 lbs you hit a shoulder blade and i don;t care bow make model with a mechanical broadhead kiss the animal good buy cause you won't see it again.It takes conetic energy to make a mechanical blade work properly,and shot placement.but if your shot is good what makes the difference in broadheads?I shoot muzzy 75 's,I have shot Rocket steele heads,hit a shoulder broke the tip off the broadhead, folded up and fell out of the deer .A fixed broadhead would have stayed in the carcuss and did some seriouse internal damage.Now say what you will about the mechanical.LOL there a joke .indians hunted for 1000 years harvest bigger animals with less sufisticated equipment than we have to date.LOL again