Barrel copper question

[laketrout59]

What would cause a cleaned barrel to have two separate spots at 4 inches and then 6 inces towards the end? Everything is very clean until you see the copper. Are they spots where the barrel is smaller diameter possibly? Shoots fine but it's odd. Still needs more rounds to get going.

 

[Zen Archery]

A clean barrel. Lack of copper fouling.

 

[laketrout59]

But why only two one inch sections a few inches apart?

 

[lancetkenyon]

Probably slightly rougher or tighter spots in the bore.

 

[VinceMule]

with a very tight fitting patch on a punch type of jag, you should be able to feel the tight/loose spots. If there are rough spots, you should be able to see them in the bore scope.

I had one barrel that coppered just forward of the throat and then the last 6 inches of the barrel, and later on I determined that the bore opened up in the middle. You do not know if the cause is from lapping or heat treat, but these types of barrels are almost impossible to tune.

Cleaning with JB with an Iosso or Montana Extreme plastic brush may become part of your cleaning routine.

 

[laketrout59]

Great

 

[Phil Rizzo]

If it's still got copper after a scrubbing. It's not clean.
Hopefully it will improve with some more rounds. Some do.

Had a wise, experienced guy tell me the best barrels get snug right before the muzzle. He called them "hummers"
But they weren't excessively loose leading up to that point.

Listen to that guy from Possum Kingdom when he offers barrel info.
How many rounds fired on yours?

 

[ArmaHeavy]

I've seen this in many barrels. Copper dispersion seems to be inconsistent.

Keep in mind that there was likely some light copper fouling thru the entire bore, but you cleaned it out already, so what you're seeing is the remnant... the worst of it. It may be a temperature/velocity thing, as the bullet moves down the bore. or, like some have said, constriction of the bore in certain areas.

If you're seeing copper, your barrel is not really clean. It's clean-ish. ThorroClean and plastic brushes will do ya right.

 

[Zen Archery]

If you want consistency stop cleaning your barrel. Or clean it exactly the same way after every shot. Shooting fouled takes less effort.

 

[VinceMule]

First line of defense is good bronze bristle brushes, and they do wear in dia. So, the best use of a Bronze bristle brush is the first 60-70 strokes and it is perhaps worn out at 100 strokes. If you keep using the brush after 100 strokes, then the bristles have lost their "spring", losing their scrubbing abilities. Scrubbing back and forth with Iosso and Montana Extreme Plastic brushes cleans the dickens out of a bore but the larger bristles do not get in the corner of the lands well.

Abrasives come in different grit sizes and there is NO standard for this. Abrasives can open bore dia as this same method is used for lapping bores after they have been rifled.

JB is very safe to use on patches and plastic brushes
JB Bore Bright(RED) is much more aggressive
A product called Flitz Bore cleaner is as good as JB, easier and more economical to use, I highly recommend it
When bores just get really nasty, the Thurro Clean does a great job, But I only use this when absolutely have to. When products clean as fast as this does, it is an indication that there are some abrasives in the product that are cutting fast. I do not want my throat and bore dia opened up from cleaning. Just because a product cleans really fast, does not mean that you should use it regularly as an aid to convenience.

For myself only, I have been making abrasive cleaners for 30 years. The abrasives come in various sizes graded in Micron size. I have ruined some barrels in the learning process, and have rounded the edges of the lands in many barrels where they still shot amazing. I have learned that it is better to change brushes more frequently and use an abrasive only when necessary, which is usually for hard carbon. Measure your new brushes with a caliper, and monitor their use in 20-stroke intervals(stroke is defined as a push plus a pull). Always buy brushes by the dozen.

Lots of ways to skin a cat, get a Teslong bore scope and develop a method that fits your needs and every barrel is like a new woman.

If you wait till your bore is fouled to the point where accuracy is lost at 200 rounds plus, the carbon may be so hard that it is impossible to get out even using very aggressive abrasives. If you re-barrel every 800-1200 rounds, you have to figure out what techniques are best to keep the barrel serviceable for your needs and accuracy requirements.

The most aggressive bore cleaner I have ever used is the Old Rem Clean in the Yellow container, and it will round the edges of the lands with repeated use.

 

[rockchalk06]

Probably slightly rougher or tighter spots in the bore.

This

Once you get the copper out, you'll see where the spot is. I see this with Browning barrels a lot. I'd bet anything, those spots left over time are what cause the pitting.

To the OP, My X-Bolt in 6GT has a SS barrel and has 3 small spots like this after my cleaning regiment. I take a mop about one caliber size larger and saturate it with Boretech Copper stuff. Work it in the bore and leave it (couple of hours) on the bad spots. That usually knocks it out without much physical effort or hard scrubbing in the bore.

Just note it in your barrel bible, book or notes. It's going to take a couple more rounds of fouling to settle it down.