I was sighting in the new Sightron I scope that day. The first three at the bottom is where it first hit with the new scope. A little adjustment and it was shooting sweet. My Knight is the LK-II model 93 Wolverine. Mine shoots #11 caps and is not 209 able. Yours must have a conversion or be a newer model.
A favorite load of the rifle is 85-90 grains of Goex 3f and a 240 grain Thompson Center Mag Express XTP. Since you are shooting Triple Se7en I would suggest start your testing at 80 grains and work up from there.
The rifle will also shoot Barnes Expanders in the 250 weight range with again the same powder charge. You just can not push the rifle too hard. When shooting Shockwaves, I can push the rifle a little harder to 100 grains of Goex 3f and still get very good accuracy.
80 grains of Goex 2f and a 270 grain Buffalo Bullet Ball-et is another great shooter. I have shots some real impressive groups with it and that load. Plus they load easy.
I shoot a lot of Pinnacle 3f, Goex 3f, and Pyrodex P out of the rifle. It does shoot Triple Se7en very well but the best seems to come with Goex 3f.
I have shot 12 rounds out of the rifle using Pinnacle 3f and never had to swab the barrel shooting the T/C Mag Express 240 grain Sabots...
Hope this helps a little...