AR15 adjustable gas block

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[ARCHIVED THREAD] - AR15 adjustable gas block

Posted: 7/16/2013 11:11:35 PM EDT

I have an AR15 with a 20" rifle length barrel that will be shot suppressed but it doesn't have an adjustable gas block. Is the adjustable gas block a must? If so what is recommended?

Posted: 7/16/2013 11:33:14 PM EDT

[#1]

There are two kinds of adjustable gas blocks--quick adjust versions that can be toggled by hand and ones that adjust with tools. Of the first class the Noveske Switchblock is considered the best, of the second I like the Seekins adjustable gas block. You can buy the Seekins gas block at Rainier Arms. Switchblocks are mostly something that comes on factory barrels.

Posted: 7/17/2013 5:44:37 AM EDT

[#2]

What are some of the reasons that would lead me to add one?

I'm considering building my first 'potentially' suppressed rifle and I'd like to know some details as well.

Thanks!

Posted: 7/17/2013 8:22:13 AM EDT

[#3]

Quoted:
What are some of the reasons that would lead me to add one?

Weapon function. If you have an overgassed AR in ANY length/gas system, a silencer will make matters worse.

You'll just have to try the set up first and see if it's problematic.

Posted: 7/17/2013 9:16:57 AM EDT

[#4]

tough to do with a pinned FH.

would you recommend going with an adjustable from the start? Any reliability issues?

Posted: 7/17/2013 9:25:54 AM EDT

[#5]

I run a JP adjustable gas block on my 11.5 sbr. It looks like a standard front sight post. After toying with the screw and adjusting it, I get no reliability issues and way less gas in the face. I like em.

Posted: 7/17/2013 9:28:41 AM EDT

[#6]

I have a full length colt rifle and its not very gassy suppressed. You'll know if its overgassed, the gas will be in your eyes out of the charging handle. This happens almost always a little with a suppressor.

I have a noveske switchblock on a carbine, which is one way of dealing with the problem.

Posted: 7/17/2013 6:43:47 PM EDT

[#7]

Will Noveske sell the pin on switchblocks by themselves? Doing a rifle length gas build and I'd like to run a switchblock, but I'd rather not use the clamp on version.

What are the other toggle options? The only ones I know of are the switchblock and the one Larue has, but they don't sell it separately.

Posted: 7/17/2013 9:49:06 PM EDT

[#8]

Check out MicroMOA, that's the one I'm considering once my stamp comes back.

Posted: 7/18/2013 3:28:02 AM EDT

[#9]

<Edited, you are going to have to register as a Dealer or Industry Partner to advertise here ......................dpmmn>

Posted: 7/18/2013 4:48:43 AM EDT

[#10]

Very interested in the micro MOA. Do you know the port sizes I would need for an 18" barrel with rifle length gas tube or where I could find out what I need?

Posted: 7/18/2013 6:06:15 AM EDT

[#11]

<Edited, you are going to have to register as a Dealer or Industry Partner to advertise here ......................dpmmn>

Posted: 7/18/2013 7:10:09 AM EDT

[#12]

Quote History

Quoted:
Below is a picture of a customer's 18" SS Stag barrel using a rifle length gas system. Port was way too big. .111"

View Quote

My GOD!

Whomever ported that barrel should be slapped upside the head. I've never heard of ANY AR that needed that much gas. Even a 16" barrel with Rifle length gas doesn't call for that big a hole.

Posted: 7/18/2013 7:36:23 AM EDT

[#13]

<Edited, you are going to have to register as a Dealer or Industry Partner to advertise here ......................dpmmn>

Posted: 7/18/2013 8:33:45 AM EDT

[#14]

That block sounds interesting.

Will the 3 position fit under NSR handguards?

Posted: 7/18/2013 10:24:44 AM EDT

[#15]

Quote History

Quoted:
That block sounds interesting.

Will the 3 position fit under NSR handguards?

View Quote

I know the two position does but not sure of the 3 position. Need a minimum ID of 1.365 for the 3 position.

Someone posted on another forum, regarding the inner diameter of the NSR: "1 3/8" at the smallest cross section (straight across), 1 1/2" at the diagonals."

If that is true, I would say yes, the 3 position should work.

Below is pic of Legion's gun at the 2013 Shot Show w/ the Govnah (2 position) under an NSR.
The NSR isn't round and kinda 'bows' out where regulator plate is so I'm pretty sure it will be fine w/ the 3 position.

Posted: 7/18/2013 11:07:09 AM EDT

[#16]

Quote History

Quoted:
Check out MicroMOA, that's the one I'm considering once my stamp comes back.

View Quote

I have one, so far I'm very impressed with it.

It's built like a tank and unlike some on the market, only needs the tip of a round to switch from unsuppressed to suppressed.

Fits under most rails. I have a Troy rail.

Easy to install and easy to swap the regulator plates, if needed.

Posted: 7/18/2013 12:28:39 PM EDT

[#17]

M16A2 port, .093.
Mk12 port, .104.

I had a 17" rifle ported .093". It ran well but got sluggish with .223. With a short can it cycled like it would at 20".

Posted: 7/18/2013 4:26:57 PM EDT

[#18]

I'd also check out the SLR DA7 adjustable gas block:
http://www.ar15.com/forums/t_3_124/610963_SLR_Rifleworks_DA7_Detent_Adjustable_Gas_Block.html

It's $100, stupid simple, and has a wide range of adjustments using a simple allen wrench you can store in the pistol grip:
Quick DA7 Operation Video

ETA: SLR Rifleworks is also a site sponsor.

Posted: 7/19/2013 6:11:57 AM EDT

[#19]

Quote History

Quoted:
I'd also check out the SLR DA7 adjustable gas block:
http://www.ar15.com/forums/t_3_124/610963_SLR_Rifleworks_DA7_Detent_Adjustable_Gas_Block.html

It's $100, stupid simple, and has a wide range of adjustments using a simple allen wrench you can store in the pistol grip:
Quick DA7 Operation Video

ETA: SLR Rifleworks is also a site sponsor.

View Quote

Or save $50 and DIY. Troy GB and a $.59 screw. I don't like the other design because it is difficult/impossible to adjust if it is under a long HG. You also will probably have to remove the suppressor for access. But you may need to mod the HG for the side access, so YMMV.