Swhacker 100gr. I haven't had one to not open. I've killed deer with "less-than-perfect shots" that would have done zero damage had I been using a fixed blade. Tracking distance is usually 50 yards max. If you are going with an expandable blade, this is by far the only one on the market that makes sense to me. The blades don't even start cutting until they are inside the deer (look up their videos for a demo). You don't lose any energy to your blades having to cut through hair and hide before getting inside the deer. The only possible downfall that I can really think of is that the entrance wound isn't always that big. so if you don't get a pass through shot, you may have trouble finding blood...especially if your entrance wound is anywhere in the back or between the shoulders.