I shoot RWS with a #11 striker and still from time to time have to dig out a slice of metal from the outside of the cap. It likes to slip under the breech plug. I keep a small screw drive on the shooting table for that reason. Granted it is not all the time, but it does happen. I have also had the striker when I cock it back, pull that metal with it, and then you do have a problem you have to dig that out or it will slow the striker down. Again, not all the time, but I do watch it.