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Brake or no brake on 10.5" 6mm arc?

Luumor Jonson

Private
Minuteman
Jan 16, 2024
4
0
Upstate NY
I'm planning on putting together a 6mm arc with a barrel between 10 and 12". I've never fired anything with that short of a barrel and don't know what to expect. Would a muzzle brake make it more pleasant or increase concussion? Unfortunately, suppression is not an option, and I may have to pin and weld, so I have to make up my mind before I can try it. This is mainly a "just because" project. Plinking and hunting if velocities will allow. I imagine doing a fair amount of prone shooting with it.

Does anyone have any wisdom to share?
 
With the short barrel, a brake will be brutal even with the mild 6mm ARC. My 13” barks pretty loud without a can or Blast Shield.

If you can do an SBR but not a suppressor, get a SIlencerCo Blast Shield, or something comparable. It’ll help. Hell, even with a 16” barrel, it’ll help with noise and concussion.
 
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My 12” Grendel isn’t bad unsuppressed, but I only shoot it suppressed.

6mm ARC will have higher muzzle exit pressure due to significantly-less bore volume.

Higher muzzle exit pressure = louder dB.
 
As Tony said just get a 16" barrel and put a brake on it or a KAK flash can. No reason to get a 10" or 12" and then extend them to 16". You get all the length and none of the velocity.
 
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If you do go with a brake, see if this one will bring you to 16”...🤣🤣🤣

iu
 
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If you end up going with a ~10" barrel, please report on what gas system, buffer system, and bolt you plan on running.
I want to do a 10.5" Grendel something bad, but I'm afraid to commit if it won't be reliable, or if it is too harsh on the bolt.
 
If you end up going with a ~10" barrel, please report on what gas system, buffer system, and bolt you plan on running.
I want to do a 10.5" Grendel something bad, but I'm afraid to commit if it won't be reliable, or if it is too harsh on the bolt.

Craddock and I were talking the other day and he had mentioned that he was spinning up 11.5" 6ARC barrels with Carbine+1 for some federal boys with great success.
 
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Craddock and I were talking the other day and he had mentioned that he was spinning up 11.5" 6ARC barrels with Carbine+1 for some federal boys with great success.
That makes more sense than CLGS because 6mm will have a lot higher gas port pressure at the shorter location.

I would push it out as far as possible, and either configure it suppressed 100% of the time, or have RifleSpeed or Bootleg adjustable gas.
 
I made my own barrel.

I forget what kind of bolt this one has. It's either one from Classified Defense or JP.
Got any pics of the barrel uninstalled? Looks to be dimpled nicely.

Very slick. These higher performance cartridges really bring the AR-15 into where it should have been from the start.

I love 5.56, but it doesn’t cut the mustard as the distance increases.
 
Got any pics of the barrel uninstalled? Looks to be dimpled nicely.

Very slick. These higher performance cartridges really bring the AR-15 into where it should have been from the start.

I love 5.56, but it doesn’t cut the mustard as the distance increases.


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