I have a question. The axis shaft is smaller in diameter than the inside of an 11/32 ferule taper on a broadhead. As a result, the end of the shaft actually fits inside the ferule 1/8 to 1/4 inch. As such, the steel broadhdead ferule surrounds the outside edge of the shaft. Seems this would go a long way toward preventing any type of splitting.
That's the way I've been shooting mine, and so far, so good. Of course I've yet to hit any big rocks or engine blocks with them. Seems more than sufficient for deer size critters though. Of course, Ozy Clint, I know you have bigger things in mind.