Heavy copper fouling

[clovishound]

I have a Colombian Mauser. My buddy gave it to me for Christmas last year. I cleaned it up, repaired and refinished the stock and am getting it ready for hunting season. For those of you unfamiliar with these weapons, mine was probably made in Austria between the World Wars. They were originally chambered in 7.92 x 57, and were re barreled in the early 50s in 30-06 for the Colombian Army who had a ton of 30-06 ammo on hand thanks to Uncle Sam.

I had shot it some this spring with mixed results on accuracy. When taking it out today I saw it consistently grouped fairly tight with one flier per group. I had symptoms like that with my Savage in .223. It turned out to be copper fouling. A good cleaning restored accuracy.

I cleaned the Mauser tonight and noticed I was still getting green patches after a fair amount of solvent, brushing, and patching with a nice tight jag.

Any advice on removing copper fouling? Should I get completely white patches after soaking with solvent and running patches through? I'm using Keen bore solvent. I've found it to be a little better than Hoppes at removing fouling.

This is an old weapon with unknown maintenance over the years. The fouling may be a dead end, and I may never get good accuracy without extensive work, perhaps a new barrel. On the other hand, getting a squeaky clean barrel may put me in decent accuracy territory. It seems a likely place to start.

Any advice appreciate.

[JEBar]

the most important thing for me, for a hunting rifle, is the first shot .... if I know I an count on the first round predictably hitting a specific point, I breathe much easier .... I've never needed a hunting rifle to deliver a tight with a hot barrel .... with that being said, having a clean barrel can't hurt .... I tend to get more concerned about lead in a barrel but, thankfully, lead is easier to get out .....

[ditto1958]

OP, if it shoots straight don’t lose any sleep over it. Clean the carbon out of the bore, and leave the copper there.

[snell]

On older MilSurp rifles I've had in the past, the bores have been very grungy with copper and lead fouling. I've had great success cleaning them with a home made electrolysis unit. A low voltage wall wart or battery pack, a cork cut to fit the chamber to plug the bore, a small diameter steel rod with three or four strips of tape to keep the rod away from the walls of the bore, a funnel for the muzzle to keep the fluid away from the outside finish and an electrolyte of 2 parts vinegar and 1 of distilled water works well. Connect the negative lead from the wart to the firearm and the positive to the rod (alligator clips work great) and you will soon see bubbles in the funnel. You are actually taking copper from the bore and electroplating the steel rod thereby removing the copper from the bore. This same system, albeit much more expensive, is available from places like Midway under the Outer's Foul Out brand name. Copper fouling will ruin accuracy and it's one of my pet peeves.

Art

[clovishound]

I went by my buddy's today, and we put the bore scope down the barrel. As suspected it showed very heavy copper fouling on the lands. I dropped by a LGS on the way home and picked up a tornado brush and some Hoppes Copper Terminator. I ran a couple soaked patches and let it sit for about 20 minutes, then ran the brush through. The first patch or two came out hunter green with a sheen of copper on the surface of the patch. I ran a few more dry patches through and will rinse and repeat until I start getting fairly clean patches out after the remover has had some soak time.

I'm hoping this will improve the accuracy a good bit.

It should.

[clovishound]

Holy copper fouling Batman. I've been cleaning on this thing all evening. Every 30 minutes to an hour or so, I've been going out and brushing, then patching, then wet patching. I'm still getting a ton of copper out of it every time. I'm not seeing the copper sheen on the surface of the first patch anymore, so maybe I'm making progress.

It does make me wonder if I'll ever get the copper out of this thing.

Also makes me wonder how many rounds were shot through it with only an oily patch run down the bore.

[Henry88]

On older MilSurp rifles I've had in the past, the bores have been very grungy with copper and lead fouling. I've had great success cleaning them with a home made electrolysis unit. A low voltage wall wart or battery pack, a cork cut to fit the chamber to plug the bore, a small diameter steel rod with three or four strips of tape to keep the rod away from the walls of the bore, a funnel for the muzzle to keep the fluid away from the outside finish and an electrolyte of 2 parts vinegar and 1 of distilled water works well. Connect the negative lead from the wart to the firearm and the positive to the rod (alligator clips work great) and you will soon see bubbles in the funnel. You are actually taking copper from the bore and electroplating the steel rod thereby removing the copper from the bore. This same system, albeit much more expensive, is available from places like Midway under the Outer's Foul Out brand name. Copper fouling will ruin accuracy and it's one of my pet peeves.

Art

Looks something like this?

[clovishound]

I've used electrolysis to remove corrosion from artifacts and old tools. Not sure I want to go this route on a rifle barrel.

I'll go out and see what an overnight soak has done. I will likely take it to the range today, even if it isn't completely clear.

[clovishound]

Well, I took it to the range last week, no difference. I went to clean it afterwards, and the patches said I was back to square one. On the advice of the local gunsmith, I bought some foaming bore cleaner and foamed and patched it over and over again for several days. I finally got to the point where I only got light blue on the patches. Took it to my buddy's yesterday and we ran the bore scope down it, and looks like I got it pretty clean. Will take it to the range this week and see if shoots any more accurately. Fingers crossed.

[GFK]

Thanks for the update.