Copper fouling... Good or bad?

[Joshboyfutre]

So I read an article the other day about cleaning copper fouling out of rifle barrels then today I watch a video with some guy saying his rifle gets more accuracy after about 50 rounds from the fouling. Whats really going on here. Should I just be getting the carbon fouling cleaned out and not worry to much about copper?

 

[redbullitt]

I would only worry if the rifle does not shoot how you want.

The copper "fouling" can help to fill in imperfections in a barrel. Some times, depending on caliber and how they are shot the barrel can get too much copper in it and need a cleaning.

My 308s and 260 have never gotten to that point... I shoot a lot of cast though so that may be part of it.

 

[readyeddy]

Copper messes up my rifle's accuracy. I've heard of carabon fouling tightening up groups but not copper.

 

[ATLDave]

A while ago, I ran across a video by an AMU rifle shooter who said that they (or at least he) had decided that the copper fouling mainly filled imperfections and was a feature, not a bug... and that they would only strip out the fouling at the end of the year. This for a guy who was surely shooting many thousands of rounds per year.

But I can't find that video anymore. Anyone got a link?

 

[Joshboyfutre]

Springtime hits I'm gonna do some experimenting, got an AR with maybe a hundred rounds thru it that I cleaned real well. Think one group fressh then one at every hundred up to 300 should tell it true?

 

[ATLDave]

Different video, but a very thorough explanation of coppering. https://www.youtube.com/watch?v=_KRUAv3Byp4

Short version - eventually it's a problem, but cleaning it before that point is affirmatively bad, speeds barrel erosion, affects zero and accuracy, etc. I'm not much of a real rifle shooter, so I express no opinion one way or the other; I'm simply not qualified. But this is similar to what I was talking about before. Take it for what it's worth.

 

[d2wing]

If you bore is rough I think it will affect it more and in a bad way. If you have a nice lapped barrel and properly broken in it should not hurt it too much. One of my rifles tends to copper up and it kills accuracy.

 

[matrem]

All rifles I've had extensive experience with will eventually lose accuracy due to copper fouling.
Just how many rounds depends on the barrel.

I too, agree that a bit of copper can aid in covering imperfections, but that only goes so far.

Most copper cleaning regiments aren't going to completely remove all of it.
Just keep it from building up too much.

Worst case I've seen was twenty or so years ago. A fella brought a Rem 7 .308 to me because he said it "no longer shot good."
I took it out and could only get my handloads to shoot about 8" groups at 200 yards.
After numerous patches and a couple days with CR 10, that rifle went to 2-3" groups at 200 with the exact same loads.

 

[taliv]

definitely a lot of variation in different barrels, but in all of mine, i've found the most consistent thing is zero copper. it's my belief that's key to single digit ES. See my recent break in pictoral log thread for more info


what exactly does having a bed of copper do to help?

 

[Bobson]

TiborasaurusRex advocates for having a certain layer of copper fouling for best results. I don't remember exactly what the benefit is, but I know he does.

He talks about it in this video (Coppering and Powder Fouling), starting at roughly the 7 minute mark, and also this one (Copper Removal Issues in Long Range Precision Rifles).

The screenshot below is taken from the first video.

 

[COLOSHOOTR]

The concensus in the precision rifle (tactical / practical) side of things is to have a little fouling in the barrel to aid consistency and thus accuracy. You'll usually see a drop off in accuracy at a certain round count where there is too much fouling. That's rifle dependent and can be anywhere on the spectrum from a relatively low round count to a fairly high one . Mine drops off around 500 rounds.

 

[taliv]

bobson, that may be optimal for barrels that won't stop coppering. shoot it until you get the "stability zone" he describes. how do you know when the stability zone is on your barrel?

follow the break in i described on a hand lapped barrel in that thread, and you don't have to worry about it for a long time. as i demonstrated, almost 200 rounds and still no copper.

 

[Bobson]

Ah, gotcha. I never really paid that much attention to that part of his series, tbh. I figured I'll rewatch those when I'm ready to shoot long range.

 

[merrill]

When two dissimilar metals are combined or connected to each other as copper fouling in a firearm bore, corrosion can result. I noticed green corrosion in my rifle from copper build up. This was in the 70's. I was unaware of the problem and didn't know how to remove the copper. I did religiously clean the bore, but never removed the copper. It takes a bit of time for this to occur.

 

[Joshboyfutre]

For the the longest time I thought just running bore cleaner thru a couple times done the trick, not even close lol u gotta really work to get that crap outta there

 

[rcmodel]

A copper sheen on top of the lands doesn't hurt a thing, and may provide best accuracy with a fouled bore.

When you start getting long strands of copper pulling out of the rifling groves on your bore brushes??

That is BAD!!

rc

 

[taliv]

let me try again...

some barrels copper foul.
some barrels do not.

if your barrel is copper fouling, then the screen shot bobson showed explains that if you clean all the copper back to zero, then you will have to wait several shots before you get the same consistency in terms of friction and bore diameter. however, it also shows you never really get great consistency, as it's always changing a little, which always hurts.

if your barrel is NOT copper fouling, then it is capable of great consistency.

 

[ontarget]

taliv, what is the best copper remover to use on a factory barrel?

 

[meanmrmustard]

taliv, what is the best copper remover to use on a factory barrel?

Ditto, id like to hear this as well. Preferably something that doesn't melt skin.

 

[Bart B.]

Sweet's 7.62 or Shooter's Choice are both good copper removers.

So is a 50-50 mix of Hoppe's No. 9 and anhydrous amonia; quite toxic but it is the best overall compared to others I've tried.

As a rough bore scrapes copper off bullet jackets and therefore unbalances them, if the rough spots are filled with copper, subsequent bullets will have little or no copper rubbed off of them. They remain well balanced and shoot very accurate.

Very smooth, properly lapped bores don't scrape copper off bullets. The best of them will not show any copper wash until about 100 rounds are fired through them. Even then, they're still very accurate as they don't change very much in that department.

Winchester 70 match rifles made before 1964 had broach rifled barrels. They were not all that smooth and had to have 3 to 6 rounds fired through them before they no longer unbalanced good match bullets. So were arsenal match barrels in both .30-06 and 7.62 versions used in semiauto NM rifles. They, too, needed a few "fouling" shots to fill the micro pits in the bore before they settled down and shot to point of aim.

 

[Gtscotty]

Boretech Eliminator works quite well, and unlike most of the other good ones, doesn't really have a smell.

The only downside that I've seen is that it will leach copper out of brass jags and turn patches blue even when the copper is out of your bore. It works well enough that I'm just going to get Nickel plated or aluminum jags.

 

[Bbear]

why a barrel 'coppers' up

Here's a video from barrel maker Lilja that may help explain why some barrels copper up and others don't.

https://www.youtube.com/watch?v=hf9zZqn00CA

In the lapped barrel, you note how smooth and symmetrical the marks in the barrel are. This barrel should copper up less and hold accuracy longer. In the un-lapped barrel, you'll see where there are rough spots and marks that lay 90 degrees to the direction of the bore. These are the areas that are picking up the copper.
For the un-lapped, a little copper may help smooth things out. But, at some point you will have uneven coppering and accuracy will begin to suffer. At that point you will need to completely clean the copper out using something like Butch's Bore Shine or Sweets or something along that nature. You will then need to re-foul your bore. Re-fouling to get back to that accuracy area may take anywhere from 10 to, I've heard, up to 100 rounds.

On the lapped barrel, you will get a little bit of copper but nothing nearly as bad as what you see on the un-lapped barrel. Most of the 'dirt' in a lapped barrel is nothing more than the residue of burnt powder. And, fouling cleans out fairly easily. Once cleaned, fouling may take as little as 1 or 2 shots and the accuracy area may last for 100's of shots.

Lapping a barrel, whether by hand-lapping or through shooting 'lapping' bullets - like Tubbs Final Finish, will help eliminate those rough spots as well as make it easier to clean.

 

[Offfhand]

Quoted from earlier post:
"A copper sheen on top of the lands doesn't hurt a thing, and may provide best accuracy with a fouled bore."

WHAT?

 

[yugorpk]

Sweet's 7.62 or Shooter's Choice are both good copper removers.

So is a 50-50 mix of Hoppe's No. 9 and anhydrous amonia; quite toxic but it is the best overall compared to others I've tried.

Just so no one gets the wrong idea and actually tries this, anhydrous ammonia is not the stuff you buy in the store. Anhydrous ammonia is a very poisonous gas that is store under pressure. "Anhydrous" means without water.

What you probably mean is Aqueous Ammonia like you buy in solution in the store.

 

[taliv]

Ontarget I have no idea. I have used shooters choice and butches bore shine with good results. I imagine they're all about the same but who knows?