I used mechanicals for several years with the confidence that they would open as designed. I only used the "top" models and brands, the ones that were supposed to be the best including Rage and Spitfire. After three failed to open on entry and hadno pass through (leaving only an enter hole the diameter of the arrow, thus a pittiful blood trail) I decided that at the very least with fixed blades I would always have a large entry hole even if they don't pass through. This can make a huge difference. I've found that with my bow, Slick Tricks shoot as good as any mechanical I've ever used and they are tough as heck.