120 grains of loose 2f is considered the max load. The rifle can handle three pellets but the accuracy is terrible. I have an original Knight Disc rifle. First off I am not a fan of 3f powder in my inline rifles. Now granted a lot of people make it work. I have just as good of results with 2f powder. Also if I had to choose between Pyrodex RS and Triple Seven 2f.. unless I was shooting conicals, I would take the Pyrodex RS every time.

The other day I was shooting two 50 grain Pyrodex RS pellets and a 300 grain XTP .452 in a HPH-24 sabot with amazing accuracy at 52 yards. I did not try it further but if groups size is an indication of one distance in relation to another, even the 100 yard group would have been good.

My rifle also shoots 200 .40 caliber and 250 grain Shockwaves real well. Here is what I would try.. kick that powder charge up to 90 grains and see what happens. And be sure to use a snug sabot and swab between shots.