I'm a long bow shooter too and with the meager experience I have, I think to embed that point in the bone like that, would have required something at least equal to or in excess of my heaviest long bow, which was 82 pounds draw weight at my 28" draw.

I'm sure that one had a lot of shaft weight and good speed behind it, not just a willow, dogwood or reed shaft.

I'm also quite sure it is a dart point - but all that is conjecture at this point. Perhaps it was a stone pointed arrow shot from a captured military musket by an indian? That is also a possibility.