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Old June 23, 2019, 12:21 AM   #1
Bernie Lomax
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Copper filings on brake

I just found some sort of copper filings or shavings on the brake of my AK-74. It's not fouling, but actual particles of copper that I can wipe off with my finger. Is this normal?
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Old June 23, 2019, 08:19 AM   #2
stagpanther
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I've never noticed copper particles on my brake--tough for me to figure out how they could get there intact if they were the result of firing. Even harder to see how they could fall there since they generally don't have bolt hold-backs. The only other thing I can see as a potential explanation is something is abrading the projectile upon muzzle exit (or a result of something in the rifling nicking).
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Old June 23, 2019, 08:27 AM   #3
handlerer2
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Have any pics? The filings could be splatter, that has solidified. I don't have any experience with brakes. I have seen the crown of various rifles painted with copper.
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Old June 23, 2019, 09:13 AM   #4
sako2
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Is it a clamp on or screw on brake?
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Old June 23, 2019, 10:19 AM   #5
Wyosmith
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That's a bad sign. Something is not aligned, or the crown is way off. It' means the bullets are touching the break, and that should not ever happen. REALLY bad for accuracy.
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Old June 23, 2019, 11:40 AM   #6
Bernie Lomax
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Is it a clamp on or screw on brake?

Screw on. It's a tiny bit loose. too.
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Old June 23, 2019, 06:38 PM   #7
Dfariswheel
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Answered more fully on the other forum you posted this on....

It's entirely normal for the AK-74 to get copper deposits or flakes on the muzzle brake.
This has a lot to do with the brake's unique design.

People don't think that copper plated bullets will copper up a rifle but they will, and the AK-74 is probably worse then the AK-47.
People are astounded at the amount of copper you can remove from an AK-74 muzzle brake and the gas block.

Depending on how big the particles are, you might have a problem with an miss-aligned muzzle brake, but with the AK-74 that's very rare due to how the brake attachment is mounted on the barrel.
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Old June 23, 2019, 06:53 PM   #8
stagpanther
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Quote:
It's entirely normal for the AK-74 to get copper deposits or flakes on the muzzle brake.
This has a lot to do with the brake's unique design.
So how does that happen? Just curious.
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Old June 23, 2019, 08:17 PM   #9
Bernie Lomax
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Quote:
It's entirely normal for the AK-74 to get copper deposits or flakes on the muzzle brake.
This has a lot to do with the brake's unique design.
It's an aftermarket brake, though, not the same type as the stock '74 brake.
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Last edited by Bernie Lomax; June 23, 2019 at 08:26 PM.
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Old June 24, 2019, 06:38 PM   #10
Dfariswheel
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"So how does that happen? Just curious".

The steel bullet has a thin copper plating to prevent rust and to help lubricate the bullet during the feed cycle.
Since the copper is plated directly to the mild steel jacket it will flake off as it's fired and exits the barrel.
The bullet is spinning at several hundred thousand of RPM and the copper plate just slings off in particles.

You seldom see this except with the AK-74 and that's because of the unique muzzle brake that catches tiny flakes.
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Old June 24, 2019, 06:46 PM   #11
Dfariswheel
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"It's an aftermarket brake, though, not the same type as the stock '74 brake".

In that case you could have a brake with the exit hole slightly too small, or the brake may not be aligned with the bore and the bullet is striking it.

Try running a snug fitting .22 cleaning rod into the barrel from the rear.
As it passes out the muzzle you can usually see any misalignment or if the hole in the brake is too small.

Also look for a wobbling brake.
The AK-74 brake is loose until a few rounds are fired, then it "solders" itself solidly to the threads with carbon buildup to the point where if you don't remove it often for cleaning, you may have great difficulty getting it off at all.
This is why a slightly loose AK-74 factory brake being a little loose is not an issue.

Your problem may be an after market brake that's not well made and is either too lose, the hole is too small, or it just doesn't line up properly.
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Old June 24, 2019, 06:57 PM   #12
stagpanther
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Quote:
You seldom see this except with the AK-74 and that's because of the unique muzzle brake that catches tiny flakes.
Cool--thanks for that.
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Old June 24, 2019, 11:18 PM   #13
Bernie Lomax
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Quote:
"It's an aftermarket brake, though, not the same type as the stock '74 brake".

In that case you could have a brake with the exit hole slightly too small, or the brake may not be aligned with the bore and the bullet is striking it.

Try running a snug fitting .22 cleaning rod into the barrel from the rear.
As it passes out the muzzle you can usually see any misalignment or if the hole in the brake is too small.

Also look for a wobbling brake.
The AK-74 brake is loose until a few rounds are fired, then it "solders" itself solidly to the threads with carbon buildup to the point where if you don't remove it often for cleaning, you may have great difficulty getting it off at all.
This is why a slightly loose AK-74 factory brake being a little loose is not an issue.

Your problem may be an after market brake that's not well made and is either too lose, the hole is too small, or it just doesn't line up properly.
That makes sense, because I filed the brake down a little too much and is a little loose (but is hasn't solderd itself, even though I've shot hundreds of rounds.)

It was domestically-produced ammo, though, with no steel in the bullet. (Hornady V-max.)
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Old June 26, 2019, 12:57 PM   #14
T. O'Heir
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"...it will flake off as it's fired and exits the barrel..." Which is way better than even thinking about the bullet touching the brake. Mind you, if the bullet did touch the brake, you'd know that instantly when the brake or parts of the brake flew down range. Probably be a big greyish cloud of lead right in front of the muzzle too.
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Old June 26, 2019, 10:50 PM   #15
Bernie Lomax
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Quote:
Mind you, if the bullet did touch the brake, you'd know that instantly when the brake or parts of the brake flew down range.
Yeah. that's what I was thinking, too. Or at least the brake and its threads would be deformed.
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