I can see it now, u draw the bow and lean towards the ground to aim. You hear this device sliding down the shaft so you rush the shot. The device blows the nock out of the shaft and who knows what happens next. In my testing with heavier arrows, heavier heads it takes a lot of weight to make a substantial difference. In target shooting at 60 yards, 25 grains in head weight alters impact less than 2" and very little penitration difference. On a recent hunt several shots were not pass throughs with normal hunting weight arrows. So we began questioning arrow weight, speed, animal size, shot placement etc. Then one in our group makes a kill and returns to camp after a 300 yard tracking. Here is the thing that will make you go hmmmm. He is 7'6" 34" draw length, 680gr arrow @ 290fps with insane KE. The shot was quartering to. The arrow enters a 210# whitetail behind front shoulder angling towards the opposite side rear flank area. No pass thru and never hit a bone but rib on entry. Doesn't make sense but it happened. I shoot at 60 and 80 yards just as most shoot at 20 and 30. My setup penetrates deeper in the target at those distances than it does at 20 and 30. Why? I believe its momentum (energy) has moved towards the front of the arrow before impact at those distances. JMHO.