I used jak hammers a couple of years ago and have not one bad thing to say. Every deer I shot, the blades opened. As far as durability, I was able to kill 7 deer with the same arrow and broadhead in one year, all went down in sight. All I had to change was the blades. They are a bit pricey for only three heads but worth it in my opinion. I have since gone back to a fixed blade but not because of problems....