While this is not normally recommend.. have you ever tried boosting the powder charge? I find the Knight with a copper bullet like the Barnes for best accuracy needs magnum charges. In loose powder I shoot 120 grains and pellets I was shooting three of them. When I was shooting them with 100 grains, the accuracy was acceptable but not what I expected. So one day I decided to really push them. That Knight smoothed right out and started really sending them down range.

Just a thought.