Palma barrel bore abnormalities

[Rtheurer]

It does not look like any of the Inclusion's of the steel itself that i have seen.

 

[Dusty Stevens]

Looks like what i see with Rust pitting. As long as its not on the crown i have had barrels still shoot lights out just as it did before. Get it out at the last inch or so... seems like that will be the end of the rifle shooting well anymore.

The moly cvomment was about how it attracts and captures moisture so you can get pitting pretty easy with moly in high humid locations like the south.

Ive seen quite a few just like that down in the south and it seems moly use and no cleaning was the common denominator

 

[Ggmac]

I agree with others . Ive seen many stainless and chrome moly barrels like that . Rust under the copper from moisture. Going from AC home or car or from hi temp at range to AC , condensation starts right away then tin worms as I call them . It occurs under the copper that usually is deposited near the end of the barrel where it cools and gete deposited .
I live in s Florida , humidity and AC dont play well with steels

 

[clowdis]

Well David, I guess the next thing to do is get some Iosso paste and "lap" the first 8 inches of your bore. If it is raised that should begin to get it out. If it's pitted there won't be any change in the appearance. The later photos look more like pitting. Don't over do it because Iosso paste is slightly abrasive. If it's shooting to your standard though I'd leave it alone until I wear out the other end of the barrel and just replace it. I've seen minor pitting have very little effect on accuracy.

 

[pdhntr]

The following story is by no means implying you don't take care of your barrels. Just what I found, and it is one case.

I had a nice SS custom from one of the better barrel companies that started giving me fits when the round count exceeded 20 rounds or so. I got my first bore scope shortly after that and found I had a bad case of the same stuff you are seeing in the top half of the barrel. I didn't know how or why it was there.

A couple years ago I helped my coyote partner build an AR with a nice SS Wilson barrel. Last fall he brought it over for me to help put on an adjustable gas block. The bore scope was laying on the bench and so I thought I will bore scope it first just to see what it looked like. I got the bore scope down the barrel about half way and it stopped with a little more resistance than should have been there. The monitor showed some brown powder on the lands and in the groove.

I pulled the bore scope out and on the very tip was some brown dust. I ran a brass brush down the barrel and when the brush came out of the muzzle it threw brown dust into the air. I put the scope back into the barrel and the brown patches were gone, but what was left looked exactly like yours.

At least in this one case, I positively know what caused it, and our mantra has become, "Stainless barrels are stain less, not rust less".

Jim

 

[DR_2297]

Had a 223 button barrel on a mid range rifle with a bunch of this stuff one time. Won a lot of trinkets with it and shot some pretty big scores.

If it still shoots and doesn’t copper up too fast then I say shoot it until the throat is gone and then put on a new one.

I think I saw one of the barrel makers state that cleaners like boretech will do this.

 

[ARK]

Read the thread on The Hida and did not learn much. They talk too much!
My barrel is essentially new, second barrel from the pair I got with the rifle when I bought it from a member here. Couple of hundred rounds on it. I am rather meticulous in keeping my rifles clean, clean them after shooting. I have similar wormholes in my Criterion barrel. I was told that they are steel impurities in the production process. From now on, I am going to scope all my new barrels and document this in my logs to see if/when this will appear again. I wonder if they are covered by manufacturer's warranty.

 

[ARK]

Had a 223 button barrel on a mid range rifle with a bunch of this stuff one time. Won a lot of trinkets with it and shot some pretty big scores.

If it still shoots and doesn’t copper up too fast then I say shoot it until the throat is gone and then put on a new one.

I think I saw one of the barrel makers state that cleaners like boretech will do this.

I did not use Boretech on this barrel. I think Bortech is fairly mild cleaner.

 

[istp79gd]

galvanic corrosion can occur when copper deposits are left in the bore combined with humidity

I called GME after he posted and he explained it further, but his post sums it up. I did shoot that barrel in May in heavy blowing mist. Gun went in the truck after the match and got cleaned later that evening. The patches looked clean but I’m sure I missed some copper- hence the result.
I found the same corrosion on another barrel (different manufacturer and never cleaned with BoreTech) so I’ve increased my cleaning regime, use an oil for storage, and purchased humidity monitors for my safes.
GME suggested shooting the barrel until the accuracy fell off, then consider trying a Tubb’s Final Finish. So far it still shoots well out to 600 so I haven’t done anything to it yet.

 

[LCazador]

I've been using lock ease before storage. Prevents that corrosion under the copper.

 

[sdespres]

I have similar pitting in two barrels. My educated guess is that it is intergranular corrosion (corrosion of the border between the steel grains). It may be related to copper deposition, but I suspect something else. There may be a susceptibility in one area just due to metallurgy. Some of the cleaning solvents we use can be corrosive and they can get down in the nooks and crannies. They certainly don't come out just by wiping or covering with some other oil or protectant. The corroded spots seem to be patches, not long streaks like copper on the lands.
One of the barrels was a Krieger and the other a factory barrel so I do t think it is maker related. The Krieger shot well for a while but then started fouling.
I agree that you may want to JB or iosso it and see how it does after.
Best of luck. I know it is quite a disappointing discovery.