Feel the Burn!!!

A while back, bought a Palmetto State 5.56mm upper as a hedge against PIAPS election.  False alarm, but never got around to assembling the thing during the ammo debacle.

Decided to give it a through going over before long term storage.  Had one of those Amazon borescopes, so decided to check the un-fired (I thought) stainless barrel

Shocked to find several inches of barrel ahead of the chamber with very noticeable copper fouling.  I suppose PSA test fires completed uppers, but enough to visibly copper foul the rifling?

Anyone seen this?  Wondering if the barrel they used was a return or something.

Local shop does not carry any sort of copper solvent, so trying to remove it with Hoppes and a ton of scrubbing.

They probably cut the chamber with a worn reamer.  The throat most likely has a burr or rough spot.  With rounds downrange it'll eventually beak in.  I wouldn't worry about it unless it is really effecting accuracy.

you guys ever tried Tubbs Final Finish? I have a box I'm contemplating on using on this rough Del Ton barrel. I JB'd it pretty thoroughly last week and it still is pretty rough

I've used Tubbs FF on my Garand that has a NOS barrel.  It really helped clean it up and reduce copper fouling.  The fouling would slightly affect accuracy after 30 or so rounds and was a PITA to clean out.  The Tubbs FF did not make the rifle any more accurate, but it did help making it more consistent with it's accuracy during sustained fire.


It is not a match barrel, but it did help a little.

As this was a PSA upper bought on sale, was not expecting anything.   Just confused that the factory proof firing of ? number of rounds would copper it that much.

Not expecting bench rest accuracy from what was supposed to be a hedge bet against PIAPS getting in office.  More of a FU than anything.

Have to say, that little Amazon borescope may be one of those things that tell you stuff you did not want to hear.  I shudder to think what some of my older guns must have looked like.

As this was a PSA upper bought on sale, was not expecting anything.   Just confused that the factory proof firing of ? number of rounds would copper it that much.

Not expecting bench rest accuracy from what was supposed to be a hedge bet against PIAPS getting in office.  More of a FU than anything.

Have to say, that little Amazon borescope may be one of those things that tell you stuff you did not want to hear.  I shudder to think what some of my older guns must have looked like.

I think I might have to get one of those so I can see how bad some of my military barrels are. Especially my Mosin Nagant.