I was taught many years ago by a person who shot black powder in competition that you always want to fire a fouling shot just before target shooting, hunting, etc. In my experience at the range now, the first shot on a clean barrel is many times well off of the rest of the groups. If I'm practicing on the range with Powerbelts and 80 gr. of powder, I only need to swab every 4 to 5 shots; I can feel when it needs to be done when loading the projectile.

I would also suggest that you try less powder. When I'm shooting 295 gr. Powerbelts for hunting, I use just 80 gr. Triple Seven. Trust me, that 80 gr. does a LOT of damage to a deer! I would suggest you start at 80 gr. and start moving up 5 to 10 gr. at a time til you find out what works best in your combination of rifle, powder and projectile.

As an aside, once you have everything figured out and just want to do some plinking, reduce your powder load to 40 gr. You will be amazed at how little difference there is at point of impact between 80 and 40 grains at 50 yards. I use that load with a patched roundball to practice sight picture, trigger control, breathing etc.; it's a lot cheaper to shoot and a lot easier on the shoulder.