Adjustable Gas Block on an SBR

[Mak8080]

So I've never ran an adjustable gas block on an SBR. It's always been just your standard gas block and the old RTV sealant trick on the CH to handle blowback.

Do they make a big difference?
Would they alter dependability with a suppressor?
Are they necessary for SBRs?

I see a lot of Syrac, MOA, SLR, Gemtech suppressed carrier on the web nowadays.

Thanks

[Bob Sacamano]

Depends a lot on what barrel you have.

[Clint]

As with any barrel length, the utility of an adjustable gas block depends on several things such as, gas system configuration, existing gas port and suppressor use.


*Background info*

Suppressors add significant gas drive.

With typical SBR barrels, this can be 30-50% extra.

For a dedicated suppressed upper, a dedicated smaller gas port is clearly the best choice.

Mixed useage gets trickier, as something should change to offset the extra gas drive.

That something can be a combination of increasing buffer mass, changing ammo, adjustable gas blocks, intermediate sized gas ports, ported carriers or just living with the increased cyclic rate.

[Furbyballer]

Swapped my slr adjustable for one of Clint's .57 gas blocks for my dedicated 10.5 suppressed gun. It is a night and day difference. It feels like a completely different gun. I love it and will be utilizing several more of these handy items for other over gassed guns I own.

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[eodinert]

For what purpose?

..to make it run?
.. to make it less gassy?

A properly set up rifle generally doesn't need an adjustable gas. It's not hard to make a rifle less reliable using one. There are a lot of factors that go into reliability that can get out of whack if you're not careful.

[bighawk]

I have the MicroMOA Govnah on my DD MK18 barrel (with the massive gas port) and it makes a significant difference in the amount of gas to the face with a can. I wouldn't shoot this gun suppressed without it. When it is time to replace the barrel I will get one set up for dedicated suppressor host and skip the gas block.

I run it with a Blue Springco and H2 buffer at .072 setting without the can and at .052 with the can and it functions 100% with all different types of ammo.

[Clint]

I run it with a Blue Springco and H2 buffer at .072 setting without the can and at .052 with the can and it functions 100% with all different types of ammo.

Which suppressor?

[Aaron_B]

Depends on what you are after...

I wanted a smooth operating rifle while attempting to eliminate gas coming to my face.

I had a 16 colt barrel cut to 10.5 and installed a syrac adjustable gas block. This combined with a LMT enhanced carrier has eliminated virtually all the gas coming back to me and gave me a very soft shooting gun. I set the gas block to allow for bolt lock back with the suppressor on and suppressor off last round will not lock the bolt back. The suppressor stays on 95% of the time so it is a non issue for the bolt not locking back.

[Mak8080]

Thank you guys for the feedback. I have a couple 10.5" LMT uppers (Non-MRP) that will have dedicated cans on them. Both the uppers are bone stock right now.

If my primary concern is dependability with a suppressor, is their a particular route that anyone would suggest?

I'd prefer not to have start "tuning" them with different buffers, carriers, adjustable gas blocks, etc for fear of losing reliability.

I wouldn't mind making them softer shooting w/ less gas to the face with a simple swap of a buffer like a Vltor A5 or adj gas block, but reliability is my chief concern.

[jstalford]

Pm Clint with the details of your setup and what you run and have him recommend a size for one of his port inserts.


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