I see that the back of the new Ashby broadhead is single beveled and sharpened. I've read that feature is to rotate the shaft (if the arrow doesn't pass through) if/when it begins to back out the wound channel, thus retarding its ability to do so. In other words, it's intended to keep the arrow in the animal, and/or do additional cutting as it backs out. Don't know if it actually works that way, but looks like it would.
I know that beveling (both single and double)and sharpening the back of broadheads has been done for quite some time, but it does raise a question in my mind. It seems to be the same principle/intent as the barbed head, and I believe that's the reason barbed heads aren't legal in some states, Wisconsin for example. (Received updated information in a subsequent post. Apparently barbed heads are legal in Wisconsin now.)
Of course, a lot of expandable heads, once they lock open, might be considered barbed heads as well. I haven't read where either of these features have become a regulatory issue in this state or elsewhere. May be another area where regulation hasn't kept pace with technology.
Difficult to decide where to come down on this issue. If the arrow stays in the animal and does additional cutting, it might lead to recovering animals that maybe wouldn't have been recovered otherwise. On the other hand, on otherwise non-lethal hits, it's likely to cause unnecessary damage and trauma, and may ultimately lead to a dead, but unrecovered animal.