rockets and similar heads open when they hit hair. your enterence hole will be the same size as the exit hole
That is what has me so curious, although a mechanical is said to open upon impact, even as fast as they could open....the arrow is already moving at a rate of speed, depending of course on how fast the bow shoots that arrow. Oh well.
Frank, I hope you are able to find out something using the camcorder, that would be interesting.