That sounds like some good shooting for the group.

BH209 is a great powder,what I have found is that it does require a very tight sabot boolit fit. I believe that any combo that takes less than 35 pounds of pressure to slide down the barrel will cause ignition problems.

There are several ways to achieve good tight sabot combos, one is try a different sabot from another supplier, you can use paper to wrap the bullet of choice in your current combo to make it a tighter fit. Knurling the bullet is another option, rolling the bullet under a file across your bench or any smooth surface will knurl it and cause it to act like a larger diameter making for a tighter fit.

Good luck and keep shooting!