Muzzle loader myth?

[TT]

Muzzle loader season is coming up and I can't find this anywhere online but everyone I talk to in person says that the more you shoot your muzzle loader the less accurate it becomes? I don't believe this but everyone else seems to. Can someone explain?

 

[Diamondback 2/2]

It's dependent on how you clean. You want to neutralize the powder, but not exactly scrub the bore completely clean. As you build up fouling your shot group will tighten up and give you more consistent groups. If you scrub it totally, the consistency is gone and the bore has changes from your last group/zero. I used to get about 15-20 shots before I had to scrub completely. Between those shots I would use soap and water to neutralize the black powder. After my groups opened back up I would scrub all the lead out and start over. If you scrub every time, it's a crap shoot.

$.02