I was doing some looking around on Grimm Reapers web site. They say their heads will close up on exit because of the inertia from the bolt slowing down so fast. The way all the hair was in the blades it looked like it had stayed closed. Due to the damage of the carcass from scavengers I didn't really pay much attention to the exit wound because I was assuming it stayed closed, I never dreamed they would close after the fact.

https://www.youtube.com/watch?v=qZOnwNS_cPw