Well, didn't get any wisdom here, so I just ordered some more NAP Killzone mechanical expanding broadheads. They have worked well on two deer for me so far. I was wondering if one might get better penetration through bone with a 125 grain broadhead than a 100 grain; or, would you just be giving up speed?
I've killed one with G5 Expanding and two with Killzone expanding. But I use the regular chiselpoint instead of the razor blade point that NAP has on their Crossbow version. Never had any trouble with the regular bow chiselpoint staying closed in flight or opening after impact. I still wonder if a heavier broadhead would be better on penetration.
I hit the buck in the photos above in the upper neck and was surprised that the spine didn't break and the spinal cord was unaffected; He bled out from a severed jugular. It certainly does not have the power of a bullet. Not even a pistol cartridge fired from a carbine barrel. My son killed 4 deer with 357 Magnum chambered Handi-rifle (short barrel). And those Fusion bullets went all the way through on broadside shots.
After I found the broken rear half of the crossbow bolt, the sprinkle of blood turned into a solid stream of a bloodtrail. He expired 20 yards after he broke the arrow and dislodged the rear half.