This problem is with a custom PacNor .458 barreled smokeless muzzle loader. Bullets
have to be sized to have no resistance at the muzzle in order to push them down to
the tighter breach end of the barrel. Even at that, carbon builds to the point the
barrel has to be cleaned after very few shots in order to again get the bullet to the
powder charge.

Suggestions?

I believe that SOMEHOW the breach end needs to be lapped in a way that does not
enlarge the bore diameter of the muzzle. What method could one go about to do that?

Talk to PacNor they are great to work with.

Purchase an air gauged barrel w/o the bore taper.
You should be able to load/shoot 100rds before cleaning in that smokeless mzloader bbl.

The bbl that you received is JUNK.

Might be able to pull it all apart and lap out the breach end with lead and abrasives, but care must be taken to not screw up the muzzle end.

If your shooting traditional lead projectiles I would not worry about it . It doesn't take much to slug up the lead to seal the bore .
Remember , black powder detonates it doesn't burn progressive .

quote:

Originally posted by kk alaska:
Talk to PacNor they are great to work with.

I agree, I have several rifles with Pac Nor barrels and they are top notch shooters, on top of that the people at Pac Nor are always friendly helpful and professional.

It should have been installed the other way around, and it should not have been choked to begin with.
I have only used two pac nor barrels; they were just adequate.

As stated previously on another forum, I had that problem with Pac-Nor in the past and won't use any of there barrels ever again. They would not stand behind them. Buy a SHilen and relish their customer service.