Copper fouling location in barrel

[AaronSkipDavidson]

The copper is stripped off the bullet as it enters the rifling. The hot gas plasma dissolves the copper into solution and carries it down the barrel. As the solution cools near the muzzle, the copper is deposited.

A smooth leade is nice, but will still create copper deposits.

 

[jarnold37]

I've got a pretty new barrel I'm trying to figure out the fouling issue in. It seems to foul very heavily with Speer and Hornady cup and core bullets. After 20 rounds, it's heavy enough that I feel the need to clean it. I'm also getting bad flier in every group of 4 shots that otherwise would be a stellar group. So, I think it's the fouling but not sure.

Anyway, looking through the borescope got me wondering about what we might learn from the location of the fouling in the bore.

In my barrel, the throat to probably the first 12 inches or so of bore has no copper. Then the copper fouling starts and gradually gets heavier, to where it almost looks gloopy near the muzzle. This is a nice, smooth mullerworks barrel and the chambering and throating job is rough. I've got probably 150 rounds through it. Performed a break in and also smoothed the throat a bit by lapping it.

So if the barrel is smooth but the throat and leade is rough, will that strip the copper off the jacket and just deposit it further down the barrel? Does the fouling description above indicate it's the rough throat and leade?

Some years ago, after chambering a smooth hand lapped barrel for a friend, he complained about the copper fouling on the muzzle end. He was breaking it in by one shot and clean. When asked by a well known action manufacturer, how was the break-in going I told him bad copper fouling. After a few questions on the cleaning method he said never shoot with a clean dry barrel. After clean put some lubricant in the bore for the first shot.On the first clean barrel shot, the friction of the bullet has the bullet basically melting by the time it reaches the muzzle. After first shot there is residue left from the first shot. But with clean barrel, it is dry metal against dry metal unless lubricated.

 

[L.Sherm]

Skipdavidson nailed it!!

 

[XxaquadogxX]

The pics show your problem. You can tell by the pics the barrel was not the problem look how nice the grooves look. Somehow get the throat polished

I have read several articles about proper break in procedure, and saw a very good interview with the owner of Krieghoff barrels. Finally a friend of mine who is a gunsmith showed me his procedure and it works the best of any that I have tried. I run a patch with Flitz metal polish through the full length of the barrel, and throat area. I then run another patch through the throat paying attention to how smoothly the patch glides over the transition area where the lands start. Then I clean it. Shoot it and always use JB, and about every third shooting session I finish my cleaning with JB Bore Bright. It has consistently shrunk my grouping as well as significantly reduced the time to clean. I finish up by running a patch with a couple of drops of Militech oil followed by a dry patch or two. The amount of metal removed is negligible, and I believe that the reduced drag on the bore actually increases barrel life. This has been my experience.

 

[Mikecr]

NEVER POLISH
No Flitz, no J-B Bore Bright
Beware any barrel maker who would suggest polishing away at their lapping.

Instead, use J-B NON-EMBEDDING BORE CLEANING COMPOUND (container with blue writing) (not red).
This matches best hand lapping, and can extend accurate barrel life -without increasing copper fouling.

Bores that foul the least have a perfect surface profile for this. It's not too smooth, not too rough. Just right.

 

[L.Sherm]

Beware any barrel maker who would suggest polishing away at their lapping

Ask ank barrel maker about shooting any bullets like Tubbs down there barrels.

 

[Mikecr]

I never said myself that fire forming should be used -because D.Tubb says it works to some benefit.
But how many barrel makers have USED as many barrels as David Tubb?
How many have personally won as much?

Tubb first merchandised FinalFinish to improve rough/bad bores. Factory bores.
I can understand why barrel makers would avoid connection of their product to that. Right?

I would be cautious of using D.Tubb's advice on barrel making (if he provided that), but not on barrel usage.
I've been using his FinalFinish/TMS for every barrel, and so far the results have passed tests for his claims.
I have also done my own destructive testing with Flitz, and seen it with a friend's use of Bore Bright. In both cases the results were an immediate and unrecoverable detriment. A big increase in copper fouling.
It's the unrecoverable part I don't understand,, and that leads me to emphasizing NEVER POLISH a bore.
But if you do that, maybe your barrel maker will say 'yeah, that's just what I wanted you to do'?
And here's a new blank for $450

No. No matter what you do, you're on your own.

 

[L.Sherm]

Factory barrels that have obvious tooling marks then yeah but why do it to a perfectly good barrel like O.P's when the pics show the obvious problem in the throat.
I'm Not questioning David Tubbs accomplishments whatsoever they speak for themselves.
Just don't see the logic in sending bullets down a perfectly good barrel and remove metal when it isn't necessary.

 

[Tac-O]

Some years ago, after chambering a smooth hand lapped barrel for a friend, he complained about the copper fouling on the muzzle end. He was breaking it in by one shot and clean. When asked by a well known action manufacturer, how was the break-in going I told him bad copper fouling. After a few questions on the cleaning method he said never shoot with a clean dry barrel. After clean put some lubricant in the bore for the first shot.On the first clean barrel shot, the friction of the bullet has the bullet basically melting by the time it reaches the muzzle. After first shot there is residue left from the first shot. But with clean barrel, it is dry metal against dry metal unless lubricated.

I never shoot down a dry bore either. I always leave a thin layer of oil in for the first shot

 

[Tac-O]

I never said myself that fire forming should be used -because D.Tubb says it works to some benefit.
But how many barrel makers have USED as many barrels as David Tubb?
How many have personally won as much?

Tubb first merchandised FinalFinish to improve rough/bad bores. Factory bores.
I can understand why barrel makers would avoid connection of their product to that. Right?

I would be cautious of using D.Tubb's advice on barrel making (if he provided that), but not on barrel usage.
I've been using his FinalFinish/TMS for every barrel, and so far the results have passed tests for his claims.
I have also done my own destructive testing with Flitz, and seen it with a friend's use of Bore Bright. In both cases the results were an immediate and unrecoverable detriment. A big increase in copper fouling.
It's the unrecoverable part I don't understand,, and that leads me to emphasizing NEVER POLISH a bore.
But if you do that, maybe your barrel maker will say 'yeah, that's just what I wanted you to do'?
And here's a new blank for $450

No. No matter what you do, you're on your own.

Factory barrels that have obvious tooling marks then yeah but why do it to a perfectly good barrel like O.P's when the pics show the obvious problem in the throat.
I'm Not questioning David Tubbs accomplishments whatsoever they speak for themselves.
Just don't see the logic in sending bullets down a perfectly good barrel and remove metal when it isn't necessary.

What are some ideas to try before I go the FF route?

And mikecr, do use just the #3 grit bullets on your barrels when you break them in? Or do you go #3 through #5?

 

[L.Sherm]

Use some JB bore paste short stroking it in the throat area only, use a bore scope to see your progress.

 

[Mikecr]

do use just the #3 grit bullets on your barrels when you break them in? Or do you go #3 through #5?

I use (3)#3, (3)#4, (4)#5 for break-in on a clean/dry bore.
10shts it's done. Back to my cleaning and pre-fouling routine.
Then every ~300 I fire (3) TMS bullets at the end of a session to dress up the lands a bit.

 

[Coues110]

If it shoots 1/2 inch groups I'd find a way to live with it if it is still accurate after fouling.

 

[Tac-O]

If it shoots 1/2 inch groups I'd find a way to live with it if it is still accurate after fouling.

It throws some nasty fliers! Otherwise I'd just let the copper stay