Blades are clean guys. That head has a 2 3/4" diameter. I've shot 2 deer with them and the heads were full of hair, meat fat etc . These are clean. As far as the o ring....no fricking clue. I agree that something isn't right, like a coyote barely bleeding for several hundred yards. If it opened, he would have bled ALOT and died soon. I don't have any answers or tricks up my sleeve, this is a head scratcher to me.