7.62 muzzle device on 5.56 barrel?

[LDB]

What would happen if a 7.62 MD was put on a 5.56 barrel? And before you get started yes, I've been a member a long time but only really got started learning about AR's in the last few weeks. It's obvious what would happen the other way around but I have no clue this way and would like to know.

[CPM]

What would happen if a 7.62 MD was put on a 5.56 barrel? And before you get started yes, I've been a member a long time but only really got started learning about AR's in the last few weeks. It's obvious what would happen the other way around but I have no clue this way and would like to know.

I'm almost certain that the thread pitch of a 30 caliber barrel is always different that that of the standard 1/2x28 or whatever and would prevent the mounting of a 30 cal device. That being said, I use an Omega with a 30 caliber end cap on all of my guns and pay a 1-2 db penalty with no discernible difference on any other level.

[GH41]

What would happen if a 7.62 MD was put on a 5.56 barrel? And before you get started yes, I've been a member a long time but only really got started learning about AR's in the last few weeks. It's obvious what would happen the other way around but I have no clue this way and would like to know.

The most common 30 caliber muzzle devices are threaded 5/8-24. The most common 22 caliber devices are threaded 1/2-28. With one of these> https://precisionarmament.com/product/m4-muzzle-thread-adapter/ you could attach a 30 caliber MD to the smaller 22 cal threads. What would happen... The 30 cal MD probably wouldn't be as efficient due to the larger than needed bore diameter.

[Stickman]

What would happen if a 7.62 MD was put on a 5.56 barrel? And before you get started yes, I've been a member a long time but only really got started learning about AR's in the last few weeks. It's obvious what would happen the other way around but I have no clue this way and would like to know.

I've done it. While it might not be perfect, it works. Use the thread adapters commonly found on ebay or Amazon.

[LDB]

Thanks guys. I have no plans to do it but something I saw made me wonder about it. I knew it wouldn't be anything like trying to fit a .30 bullet through a .22 opening but wondered what it might do. Thanks again.

[GrumpyM4]

I've done it several times. Run AAC .30 cal blackouts on 5.56 guns with a thread adapter.

Matter of fact i'm currently using a 5/8x24 direct thread mount with 1/2x28 adapter on a gemtech blackside to suppress my SBR Uzi.

Greatest versatility with least expenditure of funds. Now I can run the Blackside on my G21SF with the standard piston setup, or on a 300blk, on the uzi, Cx4 SBR, or even Beretta M9 with the direct thread mount and 1/2x28 adapter if I so choose.

Since they're all play toys and not "working guns", I don't care that the suppressors (G9, multimount, blackside) all bounce around from gun to gun depending on how I feel on any given day.

[fledge]

Some 223/556 barrels only come with 5/8-24 threeds. ARP and Wilson barrels come to mind. So yeah, that’s what you do.

[Rascally]

Some 223/556 barrels only come with 5/8-24 threeds. ARP and Wilson barrels come to mind. So yeah, that’s what you do.


These same barrel manufacturers also make 223/5.56 bore muzzle devices with 5/8-24 threads to fit their barrels. With flash hiders I don't see how it matters anyway, but brakes and suppressors should be the proper bore size to work their best.

[Amicus]

As fledge pointed out, some barrel makers advocate this. The text below is from a Wilson Combat barrel description (I have never tried one of these and have no personal experience):

NOTE: This barrel is machined with 5/8”-24 threads at the muzzle-this allows for a thicker bore diameter than standard ½”-28 threads. This will ensure that your suppressor has perfect bore alignment and will enhance permanent muzzle device pinning/welding. We have found no performance differences between using a .30 cal muzzle brake/flash hider with 5/8-24 threads on a 5.56 barrel and that is what we suggest.

[czgunner]

I think that YHM now bores all (30 cal and smaller) of their rifle mounts to .30 cal regardless of thread pitch.

[Maize]

Didn't knights armament just come out with something like this?

[blade_68]

One other advantage to using 5/8 muzzle device thread on 5.56 less chance of someone trying to crank on to stupid foot lbs and jacking up the muzzle/ rifling.... Something I was informed of by few that make or work on barrels.