Shot one doe last year with the 2-blade,huge entry hole. I did't get a pass through the arrow hit the opposite foreleg. I shoot 60#, the shot was about 15yds the deer went about 80 at a full gallop. I have not had problems with them opening prematurely, but I'm pretty good about checking them all the time. I shot the actual BH many times at targets with no misfires. I do use RickJames suggestion of putting a small orthodontic rubber band on the cross junction, this helps keeping them locked in and out of the quiver. During practice I noticed you can get about 3 shots from an o-ring but I would use a new one every time when hunting.