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Copper Fouling from Hell

OK! If anyone has an answer they will be here!
I have a 9mm pistol barrel with a 'blob' of copper fouling in the corner of a land/groove about 1/2" forward of the chamber. I suspect some of the blasting ammo I broke the pistol in with utilized thinly plated bullets. The blob is taller than the height of the land and about 1/8" long. So far I have tried Sweets about six times in 10-15 minute intervals - nothing. Soaked in Shooters Choice all day - nothing. JB CLeaner twice - nothing. Finally got a dental pick in there and scraped as much as I could but there is still a small amount left that will not budge. Aside from just shooting it as is does anyone have any other ideas? Electrolysis?
 
Welllll,, I almost hate to tell it around here, but over the years, a lot of us lead bullet shooters have had to use a stainless brush to scour our pistol barrels after getting carried away with the wrong load/bullet combination.

I always used plenty of oil, and wonder of wonders, my barrels were never ruined; or even scratched as far as I can see. I'm pretty sure that it would work on your copper fouling. jd
 
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This is no match grade barrel. CCW only. I already polished out the few scratches that were there and the pistol still shoots great. However the 'blob' is forming again in the same spot. Argh! Will give Patch out a try. Too bad Outers stopped making their electrolysis unit...
 
Another vote for CR10 and then JB the hell out of it after the copper is gone.
 
Check Brownells. They (and others) sell brass screen "patches" for cleaning black powder/shotgun and pistol chambers with excessive lead/wad deposits. Shooters Choice ( and others)also has "lead remover" solvents.
 
Check Brownells. They (and others) sell brass screen "patches" for cleaning black powder/shotgun and pistol chambers with excessive lead/wad deposits. Shooters Choice ( and others)also has "lead remover" solvents.
The issue is copper not all the things you listed. dedogs
 
OK! If anyone has an answer they will be here!
I suspect some of the blasting ammo I broke the pistol in with utilized thinly plated bullets.
The "thinly plated bullets " I took to mean that you may have used Berrys or other copper washed lead bullets for your blasting ammo and the lead may be the start of the build-up.
 
I'll bet on a burr as well. The bullets down the tube so far have factory of various brands but I suspect the Blazer Brass rounds were plated bullets as Speer uses plated technology for their Gold Dot bullets so one must assume they would use it for their budget ammo as well.
Thought about the lead removing brass screen material as I have had good luck with it for lead fouling but this copper 'blob' is one tough cookie! Will get it down to bare metal and see what is underneath it all.
Thanks for the responses and good humor!
 
KG-12 could be helpful to you. It really does "eat" copper. There is no showy blue color or anything like that, but the copper dissolves.

When I started using it, I did the overnight soak a bullet test. It was the only solvent I tried that actually reduced the size of the bullet.

I've let it sit in barrels for quite a few hours with no ill effects (I only use stainless barrels - take that into consideration).
 
OK! If anyone has an answer they will be here!
I have a 9mm pistol barrel with a 'blob' of copper fouling in the corner of a land/groove about 1/2" forward of the chamber. I suspect some of the blasting ammo I broke the pistol in with utilized thinly plated bullets. The blob is taller than the height of the land and about 1/8" long. So far I have tried Sweets about six times in 10-15 minute intervals - nothing. Soaked in Shooters Choice all day - nothing. JB CLeaner twice - nothing. Finally got a dental pick in there and scraped as much as I could but there is still a small amount left that will not budge. Aside from just shooting it as is does anyone have any other ideas? Electrolysis?

I'd go for electrolysis as you suggest.
Use a mobile charger, a small rod which must be isolated from the barrel and use a solution of 1/3 each of the following. The chamber end must be water tight.
Tap water
White vinegar
Liquid ammonia.
Connect the + possitive to the barrel and the - negative to the isolated rod and wait for some 20 minutes.
If the result is not fully achieved, change the liquid and repeat since blue doe not come up with the bubbles.
Never above 4.5 - 5 volts as power source!!!
 
Regarding the Gold Dots. I love them as a carry ammo choice. In the ad link sent above even they say the core is bonded to the jacket material "one molecule at a time". Same as Federal Fusion. Same as plating technology.
All good bullet choices in their intended uses. Frankly I have never had an issue with plated bullets before and I am not 100% sure that plated jackets are the issue in my pistol. A void or crack at that point of fouling could cause the issue. I simply need to deal with it in an economical manner.
 

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