I didn't shoot the arrow but was sitting next to the guy that did and I cut it out.

NAP shockwave 100gr. Shot out the window of a Double Bull Blind, not through the mesh. Antelope buck 27 yards, hit high and ended up witha spine shot. Buck dropped in his tracks but had to shoot him again in the chest. Dissected out the arrow in the back and the broadhead was completely closed and buried in the vertebrae with the blades in the closed position. Complete malfunction, I'm not even sure how that happened. Broadhead penetrated the bone with the blades in the closed position.

I saved the bone with the head embedded and sent NAP a letter to see if they wanted it and never heard from them.