9mm AR barrel Accerory

[918v]

I'm having a 9mm AR built and ran into an issue. The barrel needs to be threaded for fun accessories, however the typical 1/2"x36mm thread will leave very little metal between the device and the bore. My awesome gunsmith suggested I go with a 5/8"x24mm and use AR-10 accesories. What are your thoughts?

 

[joemusso]

Re: 9mm AR barrel Accerory

im pretty sure you can get some 9mm accessories in 5/8-24

suppressors, brakes ect.

 

[ORD]

Re: 9mm AR barrel Accerory

DAMN! Nevermind...I misread your question. Sorry 'bout that.

 

[GBTX01]

Re: 9mm AR barrel Accerory

do you plan on putting a can on the rifle?

 

[762frmafr]

Re: 9mm AR barrel Accerory

My 9mm AR-15 barrel is threaded 1/2-28. As well as 90% of the 9mm AR-15 barrels on the market. I don't see a problem.

ETA: Not only that, AR-10 accessories are generally .308 diameter holes...that is smaller than 9mm.

 

[918v]

Re: 9mm AR barrel Accerory

I may put a can on it in 10 years from now after I leave CA.

The issue is the thin wall of metal surrounding the bore and the resulting accuracy robbing constriction once the device is tightened.

 

[762frmafr]

Re: 9mm AR barrel Accerory

I run a suppressor on mine. Almost all of the thread on 9mm suppressors are threaded 1/2-28. I completely understand what your gunsmith is getting at but it is a baseless concern.

 

[SABuzzard]

Re: 9mm AR barrel Accerory

What kid of accessories are you planning on installing? Military and LE have been using the 1/2x28 and 1/2x36 pitches for years without problems.

Keep in mind that most 5/8x24 accessories are set up for the 7.62 round. You'll have to bore out or customize brakes, flash suppressors or other devices. I'd be surprised if there are many 9mm suppressors offered with the 5/8x24 pitch. You may end up having to use an adapter or customize some other solution.

I'd say stick with the standard 1/2x28 or 36. Just don't install accessories with a pipe wrench and cheater bar

My 9mm AR 15 SBR runs fine with the 1/2x28 threads

 

[918v]

Re: 9mm AR barrel Accerory

The issue is the extremely thin bore walls. The concern is if the muzzle is that thin, the bore will actually open up like a funnel and ruin any accuracy I may gain by using a premium blank and a match chamber.

I don't care about having to open up holes. That's cheap to do.