I shoot a Knight Disc Extreme in 50 cal. I began having this problem right after I bought it and found this out and from trying it works. This person shoots for Knight Muzzleloader Team.

1. After EVERY shot, run a mildly damp patch 1 time down barrel and
out.
2. Then run a dry patch 1 time down barrel and out. No more,no less.
3. My groups cut to less than half, have never had this problem again.

I shoot 100 grains 777 loose, Horn. SST 250grn.
And yes, dump the powder. I keep mine no longer than 2 years. No matter who made it or what type for muzzleloaders.

Try a different bullet and a new can of 777

i shoot a Remington genesis with 80 gr ffg t7 and 240 gn hornady xtp mag. good groups at 100yds

I shoot American Pioneers "jim Shockeys gold" and thats all i shoot. I use 80 Grains powder and a 250 grain Tompson Center bullet and i can drive nails at 100 Yards and shoot 1 inch groups at 130yrd havent tries 150 but, i feel confident in my setup and it has proven itself in my opinion.. I would give it a try!

I had one last yr and missed two does and shot a 145 buck, then missed a monster 180. Couldn't figure it out. Then I realized my scope was lose. Stupid you would think, it was just lose enough to move each shot. So I took it off and shot iron sights. One shot at the monster and the front sight popped off. You get what you pay for.

I have the mag bolt as does my father. My gun sits in the safe and hasn't moved in like 8 years, neither has my dads. We both shoot Omegas now. Either way, I feel your frustration with the mag bolt. I could not get a decent group within 6" and my father was lucky when it found paper. Both of us has great optics and take good care of everything we own. I chaulk it up to that model CVA being just a low quality gun. CVA does make other very good guns but that one forget it. Maybe on the ML page sopmeone will have some advice for you. I know I spent enough money on bullets and what not with that thing to last a lifetime trying to get it to group.