12ga barrel wear - normal and not dangerous?

[MetalgodZ]

The new shotgun I picked up seems to have a section of wear that looks somewhat like rifling right at the beginning of the barrel, maybe 3 or 4 inches from where the bolt sits when there's a shell chambered. I can't tell how deep it is - it's too far in to feel it with a finger - but I'm assuming that it's from shooting rifled slugs, since it looks roughly like the rifling on a slug, except that it's about 2-3 inches long.

Normal?

Nothing to be concerned about?

I shot a good dozen 00 buck shells out of it on New Years Day, with no failures...but being new with shotguns I figured I'd ask rather than lose an eye a couple of boxes of shells in.

 

[vellnueve]

Are you sure it isn't just lead fouling?

 

[mac1911]

what type of shotgun? is it a magnum ? it could be a dirty area in the forceing cone area
Also I shoot 2 3/4 shells in my 3" magnum and the slight area in the chamber ahead of the 2 3/4 hull gets kinda dingy. Much like shooting 38sp out of 357mag. you will develop and crud line with the shorter round.

I hardly doubt a lead slug can wear a modern barrel. I dont even want to know the shot count for that.
My quess is a dirty barrel and maybe someone did shoot some riffled slugs through it the groves are showing in the fouled barrel?

Another possible: Maybe the barrel is so dirty that the grooves in a rifle barrel are clogged solid?

 

[Jose]

Forcing cones are the roughest part of most factory shotgun barrels, full of tool marks. You probably have some lead smears on the forcing cone, and since the slug is starting to rotate, that would give the smears that spiral look.

Clean it.

 

[MetalgodZ]

Thanks for the suggestions. Didn't even thing about the forcing cone.

I'll pick up something to get it clean...