Carbon fouling on muzzle crown

[Pilotscrappy]

So the stock barrel on my rpr is getting up there on round count, and my accuracy is starting to open up. I used to be able to consistently shootin. 5-.75. Now I'm mostly shooting an inch to inch and a quarter @ 100 yards. I figured it was the barrel wearing so I tried seating my reloads longer and haven't really gotten accuracy to improve.

I then took my muzzle brake off and discovered pretty bad carbon build up. I had never cleaned the muzzle crown before (my first precision gun), so now I'm wondering if this carbon buildup could be the culprit of lose of accuracy.

Should I attempt to clean./scrape off the carbon buildup or. Will I do more harm than good? Here is a couple pics of the crown
Stock barrel on the 6.5 has 1800 rounds.

 

[Temper]

Soak it with some good solvent(Boretech or Gunzilla work best in my experience) and let it sit for a few hours. Hit it with a nylon brush after, don't worry about getting every spec of carbon. IF you must get every bit of carbon off, get some fine steel wool and lightly work it off while still soaked with solvent.

 

[Brux]

That looks shitty. I would clean it if it were mine. I always take my breaks off and clean crown and break when I clean my rifles.

 

[Pilotscrappy]

That looks shitty. I would clean it if it were mine. I always take my breaks off and clean crown and break when I clean my rifles.

Something I fully plan on doing with my next barrel and brake lol, yeah I obviously let this go way to far..

 

[Tnc]

A little CLR on a q-tip will dissolve that right off and make it look like new again. Just be sure to run a patch in the barrel good after to make sure you don’t leave any CLR on it.

 

[Steel head]

As mentioned above the CLR works wonders.

It’s amazing how much carbon can be on the crown and still shoot well.

That said I had a bunch of carbon on my last 260 barrel and suddenly it shot like crap.
The cause was a chunk of carbon broke off like a piece of pizza missing.

 

[Cjwise5]

Carbon buildup on the crown and in the brake most definitely negatively effects accuracy. Clean that baby.
Also, 1800 rounds is probably getting close to max depending on how fast you run em.
I haven’t had a single one of my 6.5’s make it to 2000 rounds.

 

[Pilotscrappy]

Carbon buildup on the crown and in the brake most definitely negatively effects accuracy. Clean that baby.
Also, 1800 rounds is probably getting close to max depending on how fast you run em.
I haven’t had a single one of my 6.5’s make it to 2000 rounds.

I don't run to hot I don't think.
42.7 of reloader 16 with a 140eld match
There coming out about 2720fps.
Even tho round count is high, it went from. Shooting good to shitty like overnight. So I'm. Wondering if it is the carbon buildup.

Either way I'll try to clean it off with clr and see what happens, I'm already planning on ordering new barrel this month.

Thanks for input everyone

 

[chevy_man]

Are there any missing chunks or is the carbon a consistent thickness?

Have you checked for a carbon ring in front of the chamber?

You may get a few more rounds, but that's generally how barrels go. They will toss a random flyer, which you attribute to wind, mistake, etc. Then they flat out don't shoot.

 

[jim996]

I found the same in my AI .308 barrel. I had nearly 1000 rounds through it before thinking to remove the brake and clean the crown. It had a thick layer of carbon build up on it.

I cleaned it by sticking the tip of the barrel into an ultrasonic cleaner with a solution of citric acid (lemon juice). The carbon came right off in under 10 minutes and the rifle is back to hitting 3 inch gongs at 600 yards now.

 

[clcustom1911]

I always take off my brake and clean it and the muzzle every 500 rounds or so. Reloder 17 is a dirty pig. MPro 7 is my cleaner of choice. I just let the brake sit in the cleaner for 10-15 minutes and it does a good job at dissolving most carbon. Nylon brush takes care of 90% of everything else.

 

[bjay]

After 24hrs with q tip...normally do this with brake that semi permanent and contoured on barrel...

 

[Pilotscrappy]

Are there any missing chunks or is the carbon a consistent thickness?

Have you checked for a carbon ring in front of the chamber?

You may get a few more rounds, but that's generally how barrels go. They will toss a random flyer, which you attribute to wind, mistake, etc. Then they flat out don't shoot.

Yes there are missing chunks and not consistent on the carbon at all....

And that's how my barrel is shooting, it will stack 3 rounds on top of each other then the other 2 rounds are like 2 inches off lol.

I haven't checked for a carbon ring in the barrel. I clean barrel and chamber every 200ish rounds. I haven't had issues with pressure etc, never thought to look for the dreaded carbon ring.

Wouldn't I be having other signs if I had a ring in my chamber?

 

[chevy_man]

I only mention the carbon ring as reloader 16 seems to be a common theme with people fighting it.

If you're already planning on a barrel, I'd clean the muzzle and see how it shoots. Then have the barrel ready as it could be 50 or 1000 more rounds before it decides it's done. But if it's shooting with a clean muzzle my cheap ass would get every round I could out of it.

 

[Strykervet]

Do you keep a round count on your rifles? I do on all my shooters. I don't bother on rack rifles and SBR's though. I'm saying because your barrel could very well be shot out but it could also just be fouled the fuck up and still have some life in it too.

If you didn't clean the crown, then I'm betting you've never stripped the copper from the bore either. The shit to use is Sweets 7.62 solvent, it's actually intended to be used to clean out MG barrels but it's good for any barrel that's had a LOT of jacketed rounds down it.

Be careful using it, you can damage shit with it and don't smell it. Well, do, but just a whiff so you know what you're fucking with here. It's pure ammonia. Dissolves copper into a green blue snot that you can clean out. This will remove all the built up copper, yeah, but that's the point. Some is good, too much isn't, and sometimes it's best to start anew.

Anyway, it'll return the barrel to the same state it was when it was new with no fouling, minus actual wear, just be sure to get ALL the Sweets out, ANY green or blue and you're not done. Don't leave any of it in your rifle. CLP is good to clean out the Sweets with. You can soak a patch and let the barrel sit overnight but I wouldn't let it set much longer. It does have to set for a while in order to break down the copper though.

I know someone is gonna come in here bitching about fucking up the bore by removing the layer of copper, but just know I'm not advocating doing this often at all. But if you've got a barrel that's fouled the fuck up, hasn't ever been cleaned of copper, ever (remember, it's blue green shit, if you don't see that, you ain't cleaning out copper) and is now shooting shit for groups, it's a LOT cheaper to at least TRY the Sweets. Who knows, your barrel could still be shit hot? And it may have less to do with the crown being gunked up than not. Only one way to tell and certainly better than rebarreling a rifle if you can avoid it.

 

[Steel head]

I don't run to hot I don't think.
42.7 of reloader 16 with a 140eld match
There coming out about 2720fps.
Even tho round count is high, it went from. Shooting good to shitty like overnight. So I'm. Wondering if it is the carbon buildup.

Either way I'll try to clean it off with clr and see what happens, I'm already planning on ordering new barrel this month.

Thanks for input everyone

I’d be surprised if your barrel is shot out as my last 260 barrel and my buddy’s last 6.5 CM barrel both got past 3000 shots.

It really sounds like a chunk of carbon blew off the crown as happened to me.

 

[Pilotscrappy]

Do you keep a round count on your rifles? I do on all my shooters. I don't bother on rack rifles and SBR's though. I'm saying because your barrel could very well be shot out but it could also just be fouled the fuck up and still have some life in it too.

If you didn't clean the crown, then I'm betting you've never stripped the copper from the bore either. The shit to use is Sweets 7.62 solvent, it's actually intended to be used to clean out MG barrels but it's good for any barrel that's had a LOT of jacketed rounds down it.

Be careful using it, you can damage shit with it and don't smell it. Well, do, but just a whiff so you know what you're fucking with here. It's pure ammonia. Dissolves copper into a green blue snot that you can clean out. This will remove all the built up copper, yeah, but that's the point. Some is good, too much isn't, and sometimes it's best to start anew.

Anyway, it'll return the barrel to the same state it was when it was new with no fouling, minus actual wear, just be sure to get ALL the Sweets out, ANY green or blue and you're not done. Don't leave any of it in your rifle. CLP is good to clean out the Sweets with. You can soak a patch and let the barrel sit overnight but I wouldn't let it set much longer. It does have to set for a while in order to break down the copper though.

I know someone is gonna come in here bitching about fucking up the bore by removing the layer of copper, but just know I'm not advocating doing this often at all. But if you've got a barrel that's fouled the fuck up, hasn't ever been cleaned of copper, ever (remember, it's blue green shit, if you don't see that, you ain't cleaning out copper) and is now shooting shit for groups, it's a LOT cheaper to at least TRY the Sweets. Who knows, your barrel could still be shit hot? And it may have less to do with the crown being gunked up than not. Only one way to tell and certainly better than rebarreling a rifle if you can avoid it.

I actually have kept up on the cleaning of copper, so I don't think that is it.

I also do keep a round count log in my data book I'm exactly 1860 rounds right now.

I'm going to run to home depot and pixkup th clr and give it a go. I guess ita very possible the throat is burnt out, it's just weird cuz it literally was shooting great then like 2 range trips later (75 rounds) it went to shooting like shit.

And like someone else posted, it will stack a few bullets on top of each other and then throw a couple random. Flyers that are so bad it looks like I sneezed as I was pulling the trigger there so far off.

Thanks for the good info. This first rifle has been a learning experience, on my next barrel/rifle I will definitely be able to treat it better haha

 

[Sig Marine]

If you have that much carbon on the crown, you may also have enough build-up in the brake to cause "bullet strike". I remove my brake and inspect the it carefully to stay on top the carbon in the ports and then clean the crown every time I clean the rifle of powder fouling after every outing. We've seen shooters have pitting issues on the crown from not removing their brakes as the build-up wants to pull moisture from the air.

 

[MarinePMI]

If you have that much carbon on the crown, you may also have enough build-up in the brake to cause "bullet strike". I remove my brake and inspect the it carefully to stay on top the carbon in the ports and then clean the crown every time I clean the rifle of powder fouling after every outing. We've seen shooters have pitting issues on the crown from not removing their brakes as the build-up wants to pull moisture from the air.

This ^^^^

I was getting some weird fliers on my last range trip, that left me scratching my head. Went to go clean the barrel (it'd been maybe 400 or so rds since last cleaned) and noticed the brake was pretty fouled. Pulled the brake, and using a flash light, I could see one side of the inside wall had little carbon bumps built up, and the tops were sheared flat by the bullet passing through the brake. Using a dental pick, I started pulling carbon off, and it literally came of in (relatively) huge chunks. Pretty sure I found my culprit. This is a barrel with less than 1000rds through it (like 650, give or take 5-10).

 

[bourbonbent]

This happens on my rifle as well. I don’t like to speak in absolutes, but carbon buildup is inevitable.

I spin the brake off when I clean, and soak the bore and entire crown, let it sit some, and clean. Stainless is very resistant to corrosion, but still it’s best to get that crud off the crown regularly. You can scrape the crud out of the brake with a bronze or similar alloy scraper, I use the tool on my Leatherman MUT for it.

It’s certainly surprising how much carbon crud can build up on the crown with a brake on, and crown concentricity is critical to repeatable accuracy.

 

[Pilotscrappy]

Well good news, the clr ate thru all the carbon buildup I had on crown and muzzle brake.

Pro-tip
Don't be a dumbass like me.
Realize clr is an acid not a gun solvent.
It will eat thru whatever it touches.

 

[BigTex]

Ouch

 

[MarinePMI]

Ummm...when using CLR, a 50/50 mix (of water and CLR) is generally considered the max concentration you want to go. Even then, it will cause a minor discoloring if left too long in it. 15 mins max time is my rule of thumb.

 

[Pilotscrappy]

Ummm...when using CLR, a 50/50 mix (of water and CLR) is generally considered the max concentration you want to go. Even then, it will cause a minor discoloring if left too long in it. 15 mins max time is my rule of thumb.

Something I wish I would have known lol I used full concentration no dilute. Let is soak for like 45 min

I came back in the garage... And I'm pretty sure my exact words were.... "well........ Fuck..."

 

[MarinePMI]

BTDT. I have a brake that is nice funky orange'ish gray now, when not oiled.

 

[spife7980]

Something I wish I would have known lol I used full concentration no dilute. Let is soak for like 45 min

I came back in the garage... And I'm pretty sure my exact words were.... "well........ Fuck..."

Ha! Mine too only thank goodness I was only soaking the muzzle brakes only I let it sit for a couple hours. Ate the black nitride finish right off it

Should still work just fine though, it’s only ugly.

 

[Pilotscrappy]

Ha! Mine too only thank goodness I was only soaking the muzzle brakes only I let it sit for a couple hours. Ate the black nitride finish right off it

Should still work just fine though, it’s only ugly.

Hhah yeah it has character now

 

[King_beardsly]

You have the new hot tread of "battle worn"