I agree 100% with Bigbulls, if you have an untuned bow leading to bad arrow flight it can affect penetration, but man it'd really have to be bad!!

I would put the cause more to where you're hitting the animal, is it possible you think it's a good enough shot that you feel it should get more penetration? Where did you honestly hit these two animals, and what was the shot angle, and how far away were they? The reason I ask is I've seen both elk and deer hit with 40# to 60# bows many times, more often than not the ones near the 60# mark have pass throughs. Even the 40# bow buried it to the flethings. Most of the heads used were either Thunderheads or Muzzys both in the 100grn to 125grn 3 blade. So I honestly doubt a different head will make a difference in this case.

I too would stay away from mechanicals on elk! Help us out here!! elknut1