I have the same set up as you except my Knight extreme is one of the older models - it still has the hex screw retaining the bolt rather than the spring release. I shoot 100-120 grains by volume of BH209. Every time I shoot, the primer (CCI Magnum 209) sticks. To get it out I have to open and close the bolt and dry fire the rifle. It's just something I got used to. Did you try a dry fire?