Muzzle Devices for 13.7" Barrel

[SigSauerP226]

Believe there are quite a few prong flash hiders that are close to or longer than 3 inches. I believe this is the one that won the flashider shootout twice and it's a little over 3 inches:

https://www.jprifles.com/buy.php?item=JPFH-556L Apparently you'd have to order elsewhere, their website says they don't ship to CA

https://www.thetruthaboutguns.com/ar-15-flash-hider-shootout/

https://www.thetruthaboutguns.com/ar-15-flash-hiding-test-2/

[ar15barrels]

Believe there are quite a few prong flash hiders that are close to or longer than 3 inches.

https://cdn0.thetruthaboutguns.com/wp-content/uploads/2015/06/FH-chart-all-data.jpg

https://www.thetruthaboutguns.com/ar...hiding-test-2/

The useful things in those articles are these:

[Jaybird]

Keep it NOVESKE and throw the Flaming Pig on it. Don’t overthink it.

[Mute]

Agree. If you just need a flash hider, might as well just go KX3 or KX5.

[tg97]

Agree. If you just need a flash hider, might as well just go KX3 or KX5.

This might sound stupid but...I don't know if I'm a fan of that look. You guys like the look of the KX3/KX5? I feel like from aesthetics point of view, you need a slightly longer hand guard to pull it off.

Called up SOL and they told me about the NOX so that's what I got. I'll test fit and measure and if that doesn't work, then I guess I'll have to consider the KX3

[ar15barrels]

Called up SOL and they told me about the NOX so that's what I got.

I cut down a barrel and perm attached a NOX today.
The barrel ended up at about 13.85" and at about 16.1" with the NOX and some shims perm attached.
The NOX measured 2.9" long.
You should be able to pass 16" with maybe 1/16" of spacers on your barrel.

[Mute]

This might sound stupid but...I don't know if I'm a fan of that look. You guys like the look of the KX3/KX5? I feel like from aesthetics point of view, you need a slightly longer hand guard to pull it off.

Called up SOL and they told me about the NOX so that's what I got. I'll test fit and measure and if that doesn't work, then I guess I'll have to consider the KX3

Understandable. Not everyone likes the look. And I agree it looks best with a handguard that is long enough to cover the barrel entirely or even partially over the FH (like with the KX5). Glad you found something. The NOX should be cool.

[tg97]

Agree. If you just need a flash hider, might as well just go KX3 or KX5.

I cut down a barrel and perm attached a NOX today.
The barrel ended up at about 13.85" and at about 16.1" with the NOX and some shims perm attached.
The NOX measured 2.9" long.
You should be able to pass 16" with maybe 1/16" of spacers on your barrel.

Sounds good Randall, NOX coming in Monday. Hopefully you can give me a little discount to help me out with gas and squeeze me in for next week haha

[tg97]

Thanks for everyone's input! As a new rifle owner, really appreciate all you guy's help

[Robert1234]

Believe there are quite a few prong flash hiders that are close to or longer than 3 inches. I believe this is the one that won the flashider shootout twice and it's a little over 3 inches:

https://www.jprifles.com/buy.php?item=JPFH-556L Apparently you'd have to order elsewhere, their website says they don't ship to CA

https://www.thetruthaboutguns.com/ar-15-flash-hider-shootout/

https://www.thetruthaboutguns.com/ar...hiding-test-2/

The JP flash hider is impressive, almost all flash hidden.

[code_blue]

I understand the intent is to go as short as you legally can with an P&W, but I've found that using a 14" flat bbl will allow more muzzle device options while still meeting the bare min bbl requirement. IIRC, BA makes a 14.0" bbl in a few configurations.

[H3nchman]

https://adcofirearms.com/shop/categories/muzzle-devices/kac-spacer/

Here you go.
13.7"
-.63"
Plus 0.25"
Plus a SF muzzle device at 2.7"
16.02"

[ar15barrels]

https://adcofirearms.com/shop/catego...es/kac-spacer/

Here you go.
13.7"
-.63"
Plus 0.25"
Plus a SF muzzle device at 2.7"
16.02"

Woah!
1/4" of spacer and the 1/10" thread counterbore on a surefire brake leaves you maybe 5 threads holding the muzzle device.
The engineers will tell us that 3 threads is all you need, but I still think it's not ideal.
I have had a few barrels through my shop where 2 threads were holding the brake and it blew off in use.

[H3nchman]

Woah!
1/4" of spacer and the 1/10" thread counterbore on a surefire brake leaves you maybe 5 threads holding the muzzle device.
The engineers will tell us that 3 threads is all you need, but I still think it's not ideal.
I have had a few barrels through my shop where 2 threads were holding the brake and it blew off in use.

Interesting. Thanks Randall. I don't have any experience with doing that. I just saw it recommended as a way to get a surefire device on a 13.7 inch barrel. I don't think it's ideal.

[ar15barrels]

Interesting. Thanks Randall.
I don't have any experience with doing that.
I just saw it recommended as a way to get a surefire device on a 13.7 inch barrel.
I don't think it's ideal.

You can put a big spacer behind a muzzle device when the muzzle device does not have a big counterbore or chamfer in the threads.
The chamfer removes a few threads from the brake so that the brake can thread all the way back on a barrel which does NOT have the last few threads against the shoulder.
Surefire has a significant chamfer.
KAC does not have such chamfer.
That's why that spacer is made for a KAC.

When you COMBINE a brake with a big thread chamfer with a spacer that pushes the brake away from the barrel shoulder, you are removing more and more threads of engagement.
The Surefire brake's chamfer removes about 3 threads, similar to a crush washer.
A normal A2 flash hider WITH a crush washer or a Surefire with minimal alignment shims will have around 14 threads of engagement.
1/4" spacer is taking away 7 threads of engagement.
Then you need some clocking shims to align which would take away another one, leaving you 5-6 threads.
The engineers say that 3 threads is absolute minimum for a threaded junction but most designers want twice the screw diameter of engagement length.
Of course we don't have 1" of screw engagement on ANY 1/2-28 threaded AR barrel since the usable threads are only 1/2" long after the crush washer.