Today, i read through your post as carefully as i could. Please forgive me if i don't understand. What i read was you are no longer having ignition issues, but are having issues with rough spots in the bore. Perhaps some strokes using J-B would help.

What i saw was 2 pellet gave excellent accuracy. It is my understanding that 85g of BH209 would be about the equivalent of 2 pellet. It seems to me, 85g of the BH, might result in the same barrel whip etc. as the 2 pellets, and thus result in the same accuracy.

If it had been me enduring the frustration of using the BH, right or wrong, i would have jumped to the conclusion that the rifle could use a bedding job.