Colt 6920 barrel update barrel nut was loose - Page 1

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[ARCHIVED THREAD] - Colt 6920 barrel update barrel nut was loose (Page 1 of 4)

Posted: 3/18/2016 4:19:43 AM EDT

The barrel was just fouled up with extreme amount of carbon on the crown.. The chips i mentioned where just carbon chipped off of carbon.. The reason i;ve never seen this before is I've never taken off a flash hider... I didn't realize carbon built up between the barrel and the flash hider like this..
I've had a friend who builds AR's look at this rifle apparently the barrel nut was pretty loose he thinks causing the accuracy problems .. Still a qc problem on colts part.. He tightened the nut and said it was good to go.

Forgive me for my mistake . I will go shoot this rifle this weekend and update again.

Posted: 3/18/2016 4:24:54 AM EDT

[#1]

It's not carbon or lead built up?

Posted: 3/18/2016 4:26:57 AM EDT

[#2]

Yeah it's carbon build up, I had the exact thing happen and It cleaned up with some elbow grease.

Posted: 3/18/2016 4:26:59 AM EDT

[#3]

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Quoted:

It's not carbon or lead built up?

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i don't think so its has little chunks of metal missing..

Posted: 3/18/2016 4:28:41 AM EDT

[#4]

Just have it re-crowned and call it good.

Reason #124432423 to build your own shit.

Posted: 3/18/2016 4:34:34 AM EDT

[#5]

Quote History

Quoted:
Just have it re-crowned and call it good.

Reason #124432423 to build your own shit.

View Quote

Yup, send to ADCO, shorten and re-crown if it's really damaged.

Have em cut it down to the legit M4 spec of 14.5 inches and pin on a vortex or blackout flash hider to make it 16 inches again. They will recrown it and it'll shoot fine.

That does look like carbon buildup in the picture though. I have plenty of barrels that look like that pic. Its caked up carbon most likely.

Posted: 3/18/2016 4:35:06 AM EDT

[#6]

Normal carbon buildup.

You can carefully scrape it if you avoid the crown...but it will come back.

Posted: 3/18/2016 4:35:25 AM EDT

[#7]

Easy fix.
Hey, do you you have a Dremmel handy

Posted: 3/18/2016 4:37:06 AM EDT

[#8]

Never PMCS'ed a rifle? Normal carbon. Trade flash hiders and forget about it...

Posted: 3/18/2016 5:10:18 AM EDT

[#9]

Posted: 3/18/2016 5:28:39 AM EDT

[#10]

Yea, that's carbon build up. It cakes on like a real son of a bitch. It's not missing chunks of metal, some chunks of carbon either flaked off or just isn't even or something. Last 5 ARs I pulled flash hiders off looked exactly like that.

Posted: 3/18/2016 5:30:54 AM EDT

[#11]

Must be his first gun.

Posted: 3/18/2016 5:32:04 AM EDT

[#12]

Good news, Bad news situation.

Good news; you obviously get to shoot a lot.

Bad news; you forgot to clean your rifle's muzzle/flash hider.

Not life threatening - enjoy!

Posted: 3/18/2016 5:35:40 AM EDT

[#13]

I wouldn't have burned 1200 rounds without figuring out what was wrong with the rifle.

Posted: 3/18/2016 5:42:27 AM EDT

[#14]

Carbon from shooting the gun. Normal. what groups are you getting ? surplus ammo with military barrel is acceptable at 3-5 MOA IMO. Yes I want one that shoots 2 MOA with surplus myself. It can be a situation where you have " It is what it is" . Nothing more to see here, WarDawg

Posted: 3/18/2016 5:47:12 AM EDT

[#15]

Can't wait to hear what Colt says

Posted: 3/18/2016 5:49:10 AM EDT

[#16]

That's build-up, not break down.

Put some carbon cutter on it, let it soak for a few minutes, then scrape it off. I have the same crap on all mine, it's normal.

Posted: 3/18/2016 5:49:33 AM EDT

[#17]

Colt is the gold standard.

Posted: 3/18/2016 5:52:17 AM EDT

[#18]

Quote History

Quoted:
Can't wait to hear what Colt says

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Ammo issue...

Posted: 3/18/2016 5:57:02 AM EDT

[#19]

its normal. Do not send it to colt unless you are trying to give them a good laugh.

Posted: 3/18/2016 6:02:01 AM EDT

[#20]

Quote History

Quoted:
Must be his first gun.

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Must be the first gun for a lot of posters in this thread. That, or they never shoot the ones they have.

Damn, it's just carbon fellas!

Posted: 3/18/2016 6:02:51 AM EDT

[#21]

IN!

Posted: 3/18/2016 6:13:27 AM EDT

[#22]

"Be glad it's not carbonite, kid"
-Han Solo

Posted: 3/18/2016 6:14:33 AM EDT

[#23]

That sucks. My 6920 is one of my most accurate ARs (if not the most accurate) next to the 6520 I have.

Posted: 3/18/2016 6:14:48 AM EDT

[#24]

Quote History

Quoted:
i don't think so its has little chunks of metal missing..

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Quoted:

Quoted:
It's not carbon or lead built up?

i don't think so its has little chunks of metal missing..

No it doesnt, that's chunks of carbon missing take the Muzzle device off of ANY rifle whee there's space between the barrel crown and the inside face of the Device and you'll see the same thing

Posted: 3/18/2016 6:16:32 AM EDT

[#25]

Quote History

Quoted:

Must be the first gun for a lot of posters in this thread. That, or they never shoot the ones they have.

Damn, it's just carbon fellas!

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Quote History

Quoted:

Quoted:
Must be his first gun.

Must be the first gun for a lot of posters in this thread. That, or they never shoot the ones they have.

Damn, it's just carbon fellas!

Since when is 2 "A Lot"?????

Posted: 3/18/2016 6:27:43 AM EDT

[#26]

Bah.
That shits on my AK barrel to.

Old flat screwdriver...scrape that shut off.

All over the piston as well.

Posted: 3/18/2016 6:55:27 AM EDT

[#27]

Quote History

Quoted:
Can't wait to hear what Colt says

View Quote

"you need to clean your rifle" ~ Colt

Posted: 3/18/2016 6:57:35 AM EDT

[#28]

Posted: 3/18/2016 7:03:21 AM EDT

[#29]

+87

It's carbon build up. Non-chlorinated brake cleaner works very well on carbon, make sure you wear gloves.

Posted: 3/18/2016 7:04:57 AM EDT

[#30]

Quote History

Quoted:

Since when is 2 "A Lot"?????

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Quote History

Quoted:

Quoted:
Must be his first gun.

Must be the first gun for a lot of posters in this thread. That, or they never shoot the ones they have.

Damn, it's just carbon fellas!

Since when is 2 "A Lot"?????

Math much? OP + 2 = 3

Posted: 3/18/2016 7:16:47 AM EDT

[#31]

My AK geta a neat star pattern that jibes with the rifling as does my benchrest, this does not affect accuracy.

My DDM4 gets a weird buildup like that and it starts making patterns rather than groups.

Posted: 3/18/2016 7:31:20 AM EDT

[#32]

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Posted: 3/18/2016 7:33:43 AM EDT

[#33]

Can you take the picture again, but this time, focus on the barrel? Your hand has stolen the focus and without finer details on the barrel, it's just a guess.

Posted: 3/18/2016 7:36:55 AM EDT

[#34]

Stick the muzzle in a small cup of MPro-7 or some other cleaner that's good at cutting carbon. Let it soak. Half hour, over night, whatever...then use a brass scraper, a piece of brass, a piece of wood or something similar to scrape off the muzzle.

That carbon can be pretty stubborn. Have you ever looked inside a suppressor that has a few thousand rounds through it? Same thing.

Posted: 3/18/2016 7:39:01 AM EDT

[#35]

lol,

Posted: 3/18/2016 7:45:06 AM EDT

[#36]

Quote History

Quoted:
Can't wait to hear what Colt says

View Quote

The OP is why customer service people hate the world.

ProTip: that is normal carbon buildup and nothing to do with Colts Q.C..

welcome to actually using your rifle as it was intended. Install new muzzle device and forget about it, it's just like every other AR/M4/M16 muzzle that has ever been just moderately used.

Posted: 3/18/2016 7:45:09 AM EDT

[#37]

Your first step prior to starting this thread should have been Hoppes #9 and a wire brush.

Posted: 3/18/2016 7:50:11 AM EDT

[#38]

I can't believe colt would put out defective crap like that!

Put that crown to a belt sander or a grinding wheel. Make sure you go at it at a perfect 90° or you will end up shooting either right or left.
If that happens, no biggie, just stick the barrel in the fork of a tree and bend it to make it shoot straight again.

Posted: 3/18/2016 7:51:48 AM EDT

[#39]

LMAO.

I hope the OP listens to what some of the posters here are saying.

Posted: 3/18/2016 7:54:43 AM EDT

[#40]

Quote History

Quoted:

Yup, send to ADCO, shorten and re-crown if it's really damaged.

Have em cut it down to the legit M4 spec of 14.5 inches and pin on a vortex or blackout flash hider to make it 16 inches again. They will recrown it and it'll shoot fine.

That does look like carbon buildup in the picture though. I have plenty of barrels that look like that pic. Its caked up carbon most likely.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
Just have it re-crowned and call it good.

Reason #124432423 to build your own shit.

Yup, send to ADCO, shorten and re-crown if it's really damaged.

Have em cut it down to the legit M4 spec of 14.5 inches and pin on a vortex or blackout flash hider to make it 16 inches again. They will recrown it and it'll shoot fine.

That does look like carbon buildup in the picture though. I have plenty of barrels that look like that pic. Its caked up carbon most likely.

If you are determined to get a new barrel, just do this instead.

Posted: 3/18/2016 7:57:43 AM EDT

[#41]

Sure it's not a ptac?

Psa shipped a few ptac barrels that looked like that.

Posted: 3/18/2016 8:00:19 AM EDT

[#42]

OP, should of put this in a tech forum. You would've gotten the same answers, sans the sarcasm.

Clean it by the method stated multiple times, take new pictures, post 'em, and take the shellacking in stride. It'll help get that 13er film off of you.

Posted: 3/18/2016 8:05:25 AM EDT

[#43]

Quote History

Quoted:
OP, should of put this in a tech forum. You would've gotten the same answers, sans the sarcasm.

Clean it by the method stated multiple times, take new pictures, post 'em, and take the shellacking in stride. It'll help get that 13er film off of you.

View Quote

Way more amusing in GD though.

Posted: 3/18/2016 8:11:46 AM EDT

[#44]

My suppressor hosts will look like that in a 100rds or less

Posted: 3/18/2016 8:13:46 AM EDT

[#45]

Has the barrel got parkerizing under the front sight base ?

Posted: 3/18/2016 8:14:56 AM EDT

[#46]

I have had ARs 30 years and never knew you are supposed to clean under the FH.

Posted: 3/18/2016 8:15:16 AM EDT

[#47]

Quote History

Quoted:
Has the barrel got parkerizing under the front sight base ?

View Quote

Better consult "the chart"

Posted: 3/18/2016 8:22:39 AM EDT

[#48]

You suck at guns. And pictures.

Posted: 3/18/2016 8:36:31 AM EDT

[#49]

Leave it. In a few million years (plus heat and pressure), it could be a diamond, and what an awesome ad that would be in the EE, diamond tipped Colt.