Does carbon buildup affect accuracy?

SlimBlundt

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This has probably been asked/answered 100 times, but please bear with me.

I have a Barrett Fieldcraft 308 with the 18” threaded barrel. It’s a #2 contour. I’m thinking about installing a Sico ASR single-port brake so I can easily move my Omega silencer between the Barrett and my P308 while in the field.

Will carbon buildup at the muzzle underneath the brake significantly decrease accuracy?
 

AIAW

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If it's encroaching on the crown, yes. If the buildup is significant around the muzzle you could see strange issues downrange due to how the gas turbulence behaves. It would have to be substantial amount though.

General rule, keep it from getting any buildup caked in there.

Type of powder definitely makes a big difference in how often you'll need to clean the muzzle behind the brake.
 

SlimBlundt

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That’s what I suspected. Seems to me, it doesn’t take more than a few hundred rounds to make the crown underneath the brake look unrecognizable. I’m less concerned about it with my ARs as they’re more “accuracy through volume” and operate at closer ranges. With the Barrett, it’s a fantastic barrel that’s already glass bedded in a carbon fiber stock with a Timney trigger. Why throw away all those advantages by letting carbon buildup wreck accuracy? Guess I’ll just thread the can on each time I use it and keep the crown clean.

For guys who have muzzle devices on long range or competition guns, how often do you remove the brake to clean? If that sucker is rockset, that must be a real PITA.

If it's encroaching on the crown, yes. If the buildup is significant around the muzzle you could see strange issues downrange due to how the gas turbulence behaves. It would have to be substantial amount though.

General rule, keep it from getting any buildup caked in there.

Type of powder definitely makes a big difference in how often you'll need to clean the muzzle behind the brake.
 

Rudy Gonsior

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Some brakes are worse than others but yes it can be a thing. The older SF 7.62 brakes for example seemed to foul about the crown and cause accuracy issues but other designs seem to work fine. I'd use blue locktite, been using it for years on brakes/adapters for years, its much easier to break lose than rockset and isn't going anywhere.
 
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FishDr

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What Rudy said - blue locktite. And mine seem to go between 5-600 rounds. I’m NOT using a suppressor tho, so that may change things.
 

Sig Marine

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I never loctite a muzzle brake; hand tight is usually enough. I remove the brake and clean the crown every time I clean the rifle. Carbon build up in the brake can become an issue and cause bullet strike so I keep the brake free of carbon as well.

Damn, that's one ugly crown. On another note, I prefer a flat crown vs an 11 degree target or recessed crown. With a flat crown you can use the edge of a plastic card to remove much of the carbon. In a worst case scenario, carefully using a razor blade held at a very, very shallow angle can cut the most difficult baked on carbon.
 
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