I have done lot's of testing with Rage 2 blades and have had the blades open in flight. Tuned or not they wont fly wellopening prematurely. Design issue??? I don't know...I know they work well. I don't want them to open until they hit the broadside of the animal. I use a rubber band (orthodonic) to keep the blades closed until they hit something. I believe it's predisessor used a band as well. I love their performance but think they're over priced...still my quiver holds 3 of them. No big deal though...if you don't like em...use something else.