I never had a problem getting them to fly. Iam nota fan of the "poly" ferrule. Some of them didn't spin true, but in fairness I can say the same thing about a number of heads.

I will tell you this for what it is worth. I shot a very large bodied buck with one. Quartering away, the shot entered around the last rib on the right side and came our the chest of the buck (between the front legs). Yes a complete passthrough even after zipping through so much tissue. The head looked to be in great shape afterwards.

I don't feel I can speak with any "game killing" authority on them being I have only killed one animal with them. I feel like there are better heads out there, but they will work. The best head made can't make up for a bad shot. On the other hand if a guy makes a marginal shot, you want everything you can get going for you.