I took 6 deer with them the first 5 were broad side shots; then a nice buck happen to be standing at an angle the arrow when in through the top of the shoulder andhit the short ribs on the far side, no exit hole. Nine hours later I found him less than 250 yards away the only blood I ever found was where he fell.
So I did a bit of experamenting I believe that you loose up to 20 percent of the arrows foot pounds just opening a mech. They work ok under some circumstances but I wil never use them again. LEE