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25-5 07-18-2012 06:07 PM

copper fouling
I have a new M1A Nat. Match. I understand to break in the barrel must be cleaned of copper and other crud. I understand the drill and will do so for break in. However, on one of the shooting shows a military marksman was cleaning an M16. He stated that after cleaning the copper out he was shooting 1 to 1.5 MOA until after about 40 shots at which time he began shooting .5 MOA. He said to leave the copper alone until around 900 to 1000 rounds, and the MOA starts to fail. My undestanding is that fouling adversely affects accuracy of 5.56 or 7.62. Experienced comments would be appreciated.

JonM 07-18-2012 06:44 PM

I dont try and clean copper out of a bore i just get the powder fouling out. Couple of clp or some hoppes wet patches run a brush down the bore once or twice to break the carbon up and then patches. Wet patch with clp if its getting stored.

It takes a lot of effort to de-copper a bore. Your bore will wear out through muzzle or throat erosion long before copper fouling becomes an issue. You can actually do more harm to the barrel through excesive efforts at copper removal. Harsh chemicals like sweets copper solvent will pit steel.

Benchrest shooters get crazed with barrel cleaning. I just dont think you need any great herculean efforts there. If it takes you more than 15-20 minutes to clean a gun i think your doing too much.

Just my opinion take it for what its worth.

therewolf 07-18-2012 09:24 PM

I had an extreme case of a copper fouled bore with a dirty Garand with nearly

disastrous results. When the bore gets so fouled your

recoil and muzzle blast starts to increase noticeably, try

@ a teaspoon of Dawn, with half a pint of Janitor's Ammonia,

and half a pint of water, well shaken. Clean the bore with patches of

the mixture with dry patches, for a couple passes, then soak the barrel with a

patch of Dexron or Mercon ATF for a few hours.

Rinse and repeat until your patches stop coming

out blue.

TLuker 07-18-2012 09:36 PM

I think every gun is different. Some take a few fouling shots after cleaning and others take a lot more before they start shooting great again. I also think every gun is different as to when fouling will make groups open up and POI change. I've heard clean after 20, 30, 100, 300, and never clean. It's just something you have to play with for your gun and see what it likes. :)

Chandler51 07-19-2012 02:10 AM

FWIW, I practice pretty much what JonM described, and it has worked for me.

I saw the ep you were speaking of, and given the fact the guy was an Army SF Sniper, I'd tend to defer to his knowledge and experience.

But that's just me.

The_Kid 07-19-2012 06:03 AM

Breaking in a barrel reduces copper fouling. As was said before, all guns are different; I'll add that all loads are different. I have loads that shoot best clean bore, some fouled and some loads shoot the same fouled or clean, copper or carbon.

This question does not have a definitive answer.

locutus 07-19-2012 03:06 PM

The best and easiest way to clean copper out of your bore is the Outer's electrochemical "Foul Out" system.

Fast, easy, and no wear on the bore.

BlueTurf 07-22-2012 11:41 PM

I have tried several liquid solvents that were designed for copper fouling removal such as Sweet's 7.62, Shooter's Choice, Butch's Bore Shine, Montana Extreme, etc. but the best stuff I have found is an aerosol foaming bore cleaner called Wipe-Out. I leave it in the bore for about three hours and it effectively and safely removes the copper fouling.

To each his own but I do not see the logic between letting copper fouling build up in the barrel. The copper was not in the barrel when it was made so it seems to me accumulated copper fouling would have an adverse effect on the bore twist. Well, there will always be more than enough experts out there, but these are my thoughts.

RustyShackleford101 07-23-2012 02:03 AM

I saw a program on guns and ammo tv. It had an army sniper talking about weapons maintenance. He said with the rifle like it was, it shot half minute groups. Upon removing the copper, the groups opened up to 1 1/2 inch the came back down to half minute in about 40 rounds. So is what I'm hearing that a little copper helps accuracy and too much degrades it? I was confused but I don't doubt our men and women who put their lives on the line. Anybody hear anything similar?

The_Kid 07-23-2012 03:34 AM


Originally Posted by RustyShackleford101 (Post 878759)
Upon removing the copper, the groups opened up to 1 1/2 inch the came back down to half minute in about 40 rounds. So is what I'm hearing that a little copper helps accuracy and too much degrades it?

How a rifle reacts to copper fouling is load specific. Take my shot today...
That missed the 1 inch target by about an inch at 350 yards. That was a perfectly clean bore.

This was shot taken 9 days before that one, with a copper and carbon fouled bore. Same distance same target with less than 1/2moa deviation.

Other loads I've developed will have a POI shift/ accuracy drop. This one is about 2moa.
I'll skip the second shot and go to the third.
If I would have kept on shooting it would have fouled to the condition that shot well, but since I don't want to waste reloading components, I don't use that load anymore.

I now load develop in an attempt to find loads that don't have a clean/fouled bore deviation... and have done so successfully in all my rifles. The sniper you speak of simply doesn't have ammo tailored to his specific rifle.

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