Thoughts on copper fouling vs. accuracy

[Laphroaig]

Barrels accumulate copper no matter what you do when they are new. I've read that some BR shooters clean after every group, others claim a fouled barrel shoots more accurately. What is your experience?

I'm certainly not OCD about cleaning my rifles every time I shoot them, but after about 150-200 rounds I feel obligated. I do try to get most of the copper fouling out with solvents. But I must say I don't really notice any improvement with accuracy, but then again I'm not a benchrest shooter either.

Does anyone else remember an article in one of the gun rags (Shooting Times?) about 10 years ago where they tested moly coated bullets vs. plain jackets? My recollection is 22-250, 1000 rounds of each bullet, shot in 100 10 shot groups from new match grade barrels (barrel was changed between bullet type) with out cleaning. Group sizes were recorded and if I recall didn't change appreciably throughout the test with either bullet. I wish I would have saved that one.

Laphroaig

 

[tuj]

I shoot mostly rimfire, so its a little different, but with my centerfires, I find the barrel does take a certain degree of fouling to produce best accuracy.

Most BR shooters will clean after a group, but they will also fire 1 or 2 'fouling' shots to burn any residuals out of the barrel and lay down a fine layer of copper in the lands.

 

[cmb3366]

Clean bores are accurate. While you cannot really see the difference in most rifles until the fouling gets totally out of hand, in my benchrest rifle you can see a slow decline after the first 20 rounds. I keep it squeaky clean and fire 1 fouler before shooting a score target or group.

 

[Jenrick]

Due to manufacturing tolerances some barrels shoot well with lots of copper and fouling, other shoot best from basically bare steel. I had a NM Service Rifle that when cleaned down to the bare steel would shoot about a 2 MOA group. As I shot it, it would tighten up, after about 25 rounds it was a .5 MOA gun all day long. It took about 300 rounds before it would start to open back up. If I knocked the fouling out it would settle right back down. It was only when I stripped the copper out that it opened all the way back up.

I have another rifle (Howa 1500 in .308) that will really goesn't copper at all, and shoots very well regardless of clean or dirty. Cold clean bore it shoots about 3 inches left and low, and after about 3 fouling shots it will do under an inch at 200 yards for as long as I want to shoot it. Cleaning it shows very minimal copper fouling.

On the other hand I have an SMLE that just doesn't care. It coppers like it's being electroplated, but shoots non the worse for it. A single round, whether of surplus or modern bullets, pretty much makes the bore gleam orange. It's a great gun to test bore cleaners on, because it will certainly show how well it takes copper out.

-Jenrick

 

[Ash]

I agree. Fouling does not necessarily mean a rifle will be less accurate. To a far lesser extent, but something that still exists, is that some rifles actually shoot very well with pitted bores. Of course, nobody would purposefully damage a bore that way, but some milsurps with sewer-pipe-looking bores can actually shoot well.

 

[CarJunkieLS1]

My bartlein barrel in my custom 7-08 likes a dirty fouled bore it won't shoot its best until 15-20 rounds are down the pipe. My Tikka T3 factory barrel likes a little copper...a clean bore it shoots MOA after 5 rounds its sub-moa and after 20-30rds its MOA again.

Each barrel is a law unto itself and for my hunting rigs MOA or better is all I care about.

 

[MutinousDoug]

I try to clean my barrels with copper solvent about once a year. My Krieger match AR goes about 1K rounds between copper treatments. I wipe the chamber and bore with GI Rifle Bore Cleaner after a match. The Krieger doesn't seem to get any more copper in the bore after 4-5 rounds than after 88 or 800 rounds and the sub MOA seems to last until the barrel gives out at 4-5K rounds.
My M1s and 03-A3 copper foul much more heavily but just Bore Cleaner seems to allow me to shoot the same or better throughout the season.
I have made one of those electrolysis bore cleaners that I'll use once on any used gun that comes into my possession just to give me a baseline but after that it's Sweet's or Butch's Bore Shine once a year or so, whether it needs it or not.

 

[Float Pilot]

My 7x75mm Mauser with a Douglas barrel that I built back in the mid 1970s was becoming fairly inaccurate compared to how it used to shoot. So I cleaned the heck of of it with bore gel and JB compound. All sorts of copper came out. Now it shoots almost as good as it did 40 years ago.


ON THE FLIP SIDE:

I also cleaned the heck out of my original 1892 rifle in 38WCF. (38-40) it was full of lead, copper and old black powder residue. Before I cleaned it, it would shoot a 3-4 inch group from the bench at 100 yards with cast lead slugs. After I cleaned it, I was lucky to get a 12-16 inch group.
The old barrel has all sorts of pits which I opened-up via a super cleaning. So now the bore is rough and inaccurate. It will probably take years of shooting to fill in all the pits again. Oddly enough it now shoots OK with copper jacketed bullets.

 

[HB]

I recently cleaned all my centerfires with copper remover. It was a pain but a lot of green goo came out. I felt good as my rifles were now "clean" but I noticed no accuracy improvement and returned to a fouled state after only a few shots.

HB

 

[TwoEyedJack]

I have read that the real issue with copper fouling is not so much the dimensional change in the barrel except in extreme situations, but that moisture can build up under the copper and rust the barrel steel. Living in a reasonably dry climate, I have never seen this.

 

[Welding Rod]

I just push a jag with a patch or two soaked in CLP (Break Free) down the bore before putting a gun a way, and then push a dry patch through the bore immediately before I go to shoot it. That is all I ever do in the way of cleaning the bore. Seems to work perfectly well, but I mostly shoot iron sights and red dots these days while primarily standing or kneeling so if there is a slight decrease in accuracy I may not see it.

 

[Slamfire]

A shooting friend of mine is an F Class National Champ. She claims that a clean barrel is less accurate and takes a number of shots before the group size stabilizes.

I have seen in my own barrels, barrels that were at the end of the accuracy lifetime, shoot well away from established zeros just after a thorough de coppering. After a few shots the barrel then goes back to zero and shoots predictably. When this happens to me, that barrel is not long for the world as I lose confidence in the thing, though once fouled, they still shoot rather well.

After rifle matches, I am now using GI bore cleaner, which is not a copper remover, to remove powder fouling and using a bore brush. Every once in a while I run JB bore paste, but I don't know just when to do that, I probably should wait till the barrel starts grouping unpredictably. Frank White of Compass Lake Engineering told me that chemical cleaners won't remove impacted material in the rifle throat and that he has seen barrels that had a lot of impacted material have their accuracy restored after a JB Bore paste session.

Maybe we ought to be doing what a number of small bore shooters do: only clean when groups get large.

I do believe that a lot of our behaviors, and barrel cleaning is one of them, is advertising induced behavior. Corporations need to sell products and they convince us that there is a need for their product. However, their claims, the culture it creates, and the behaviors we adopt, are never tested scientifically.

 

[Walkalong]

Benchrest shooters clean after each group but they don't scrub them squeaky clean. I also fired one fouler before even shooting a sighter to get a group started.