It doesn't matter, Frank. The blades don't hit their full cut diameter until they're behind the insert on any swing blade design.

When both heads are sticking out the back of the target the same amount, then that proves what I've been saying all along. You have constant friction on the arrow shaft in foam targets and that is what stops the arrow.

Foam stops arrows by friction and, to a lesser degree, resistance to the point/blades (I've had steel blunts penetrate just as deep into foam as field points). Foam is pushed out of the way of the shaft, but the foam is constantly squeezing around the shaft as it passes thru.

When living flesh is cut, the flesh pulls away some from the site of the cut leaving little friction on the shaft. So, if the arrow is stopped, it is stopped mainly by resistance to the point/blades and friction is secondary. Two different materials, two different forces taking the lead role to stop the arrow. That's why you cannot correlate penetration data you've obtained from foam to actual results in flesh and bone.