Bob, my question is, what do you consider to be bone robbing penetration hits?
I agree 125 is a bit light. I like 165grn plus but really nothing over 200grn give or take a few grains! Arrow of use is irrelevant to me, as long as it's tuned to your draw weight & setup & doesn't porpoise to the target loosing valuable penetrating energy!
Head weight is necessary to a degree, I like the best of both worlds. I want a stable arrow with respectable punch with a razor sharp head.
To me, respectable punch is acquired according to each individuals draw & setup. A 550 grain arrow out of my 56# longbow tipped with 165-200grn 3-bladed head will penetrate any bone on an elk where vitals are on the other side out to 35 yards on doable shot angles. This would include quartering to you frontal shots to broadside shots to quartering away shots.
A balanced outlook is needed to entertain various angles & distances, this can keep trajectory in balance & not be overboard one way or another!
If all shots were 20 yards & under & from treestands, then I can see excessive head weight being under control with minimum trajectory & great penetration. But for all around elk hunting perspective one needs a setup closer to what I've mentioned to keep all avenues open & increase his odds of success, yet not sacrifice penetration or trajectory issues!
With these thoughts, one can hunt game such as deer & elk with total confidence! Head choice is a personal decision.
ElkNut1