does pitting in chamber area seriously affect accuracy?

[Salty]

Try some cream of wheat filler between the powder and ball for a cheap fix. It will raise the ball up to the good rifling. And it raises pressure to ensure a complete burn of the black powder.

Very interesting

 

[M. De Land]

I bought a T/C Hawken 45 cal about a year ago. SN indicates it was made in the '70s. It shoots ok but not consistently accurate enough for our monthly matches, even off a bench rest. I looked at the entire bore with a bore camera. The chamber area and about 6" forward of the chamber have plenty of pitting. Looks like it was not cared for in the past. The bore forward of this pitted area is shiny and very little pitting.
I shoot a 440 LRB with a WonderLube .018 patch over 45g Swiss 3f.

My question is this...does this pitting seriously affect the accuracy at 25-50 yds? Is it feasable to replace the barrel? will it improve the accuracy?

Thanks in advance

Salty

If it were mine and I did not want to re-bore or line then I would pull the breech plug and hand lap the barrel with poured lead slugs and lapping compound starting with 220 grit and progressing to 320 and finishing with 400. All that is needed is to get the rough outer edges of the pitting smoothed enough so it does not tear patch material. The pits do not need to be entirely removed to restore good accuracy if patch integrity is restored. The barrel will likely shoot as good as when new if this condition is met all else being the same. Pitting does tend to make them foul a bit faster but if one wipes between shots ( a good accuracy practice any way) it is a moot point.
Experience of having hand lapped many barrels over a lot of years has taught me much about restoring accuracy , and formerly held ideas, mostly all of which were based on speculative notions in print and no actual experience to back them up.

 

[M. De Land]

If it were mine and I did not want to re-bore or line then I would pull the breech plug and hand lap the barrel with poured lead slugs and lapping compound starting with 220 grit and progressing to 320 and finishing with 400. All that is needed is to get the rough outer edges of the pitting smoothed enough so it does not tear patch material. The pits do not need to be entirely removed to restore good accuracy if patch integrity is restored. The barrel will likely shoot as good as when new if this condition is met all else being the same. Pitting does tend to make them foul a bit faster but if one wipes between shots ( a good accuracy practice any way) it is a moot point.
Experience of having hand lapped many barrels over a lot of years has taught me much about restoring accuracy , and formerly held ideas, mostly all of which were based on speculative notions in print and no actual experience to back them up.

The reason pitting is not as disastrous to accuracy as speculated is because once the perimeter of the pit is lapped smooth and does not tear patch or lead from a bullet, the pit body fills with lube and fouling creating an almost smooth, original bore surface as far as projectile is concerned .
All a bore needs do is spin the projectile on center line axis and not cause any deformation of it. If it can successfully accomplish these two jobs accuracy can exist.

 

[Salty]

The reason pitting is not as disastrous to accuracy as speculated is because once the perimeter of the pit is lapped smooth and does not tear patch or lead from a bullet, the pit body fills with lube and fouling creating an almost smooth, original bore surface as far as projectile is concerned .
All a bore needs do is spin the projectile on center line axis and not cause any deformation of it. If it can successfully accomplish these two jobs accuracy can exist.

Good information. Thank you.