Adjustable Gas Block

[sucker76]

I've got more pieces to my 6.5CM AR build and need help with an adjustable gas block. The limiting factor is the barrel diameter at gas port is 0.875". I've found two. Superlative Arms gas bypass block and JP adjustable gas block. Does anyone have opinions one way of another on these two or any other I missed?


The shameless showoff

 

[smittyb]

SLR Rifleworks Sentry 8
Best adjustable gas block out there, great customer service.
They may be a bit slow now, as they are right in the path of Hurricane Irma.

 

[Swarf]

Are you expecting overgassing problems, or are you just wanting an adjustable gas block just in case?

Nice build so far... but is it just me or does that hand guard look like it's rising a bit relative to the barrel?

 

[sucker76]

Are you expecting overgassing problems, or are you just wanting an adjustable gas block just in case?

Nice build so far... but is it just me or does that hand guard look like it's rising a bit relative to the barrel?

The barrel and hand guard are just mocked up on the receiver. They aren't screwed down. I just wanted to see it together.

Yes I'm expecting overgassing. I've read lots of posts about needing AGB. The truth is I'm sold on them and every AR has one.

 

[sucker76]

SLR Rifleworks Sentry 8
Best adjustable gas block out there, great customer service.
They may be a bit slow now, as they are right in the path of Hurricane Irma.

I'll check them out, thanks.

 

[sucker76]

One more question; If you had the choice would you get a set screw type or clamp on type?

 

[smittyb]

Set screw

 

[sucker76]

Set screw

Can you explain? I have only used set screw type but have been told the clamp on can be more accurate because there are no pressure points on the barrel.

 

[Mungle]

Set screw if your barrel has dimples at the gas block location. Otherwise, clamp on (my preference).

I have heard the same about the pressure exerted by the set screw and would like to see evidence. Makes sense: when an engine block is align honed for maximum precision, it is done with as much of the engine mocked up as possible so as to include the distortion that bolting it all together creates.

 

[smittyb]

I have seen clamp on's leak when tight. I have not seen set screw type leak when tight.
As for the pressure point, I don't know. Seen plenty of accurate guns with them.
I concur with the align honing/torque plate reference, but we are talking about a few inch pounds here vs 100+ foot pounds.

ETA:
Also, it is very easy to dimple your own barrel.

 

[sucker76]

Fair enough. I've dimpled one barrel already and can do it again. I have never had a clamp on but was reading pros and cons to each.

 

[cajunautoxer]

I have several rifles that have a JP adjustable and i havn't had any issues. A couple of rifles I'd say have close to 10k rnds each through them

Sent from my SAMSUNG-SM-J320A using Tapatalk

 

[Swarf]

The barrel and hand guard are just mocked up on the receiver. They aren't screwed down. I just wanted to see it together.

Yes I'm expecting overgassing. I've read lots of posts about needing AGB. The truth is I'm sold on them and every AR has one.

Fair enough. FWIW, I myself take the opposite approach and prefer to keep the gas system as "stock" and "mil-spec" as possible, for simplicity and reliability. I've built AR15/308's of various calibers and not one has needed an adjustable GB. In fact, I bought a Radical Arms adjustable a while back just so I'd have one if I run into problems with a new build, but it has sat in my parts bin since. I probably will need it when I eventually get a suppressor for the 300BLK.

Just my $0.02 worth

 

[sucker76]

I will suppress the 6.5CM. I have an Odin Works adjustable gas block on my suppressed 300BLK and it is about half open. It helps keep gas out of your face.

Also remember, there is no mil spec for AR-10/LR308 since it was never military adopted.

 

[popper]

I have 4 syrac blocks, one is clamp on. No problem with any. Note: if you shoot PB cast they may lock up on you. Then you get to try to find some mercury.

 

[smittyb]

I have no first hand experience with Syrac, so I can't say if they are good or bad.
But before you buy one, I would do a quick google search on Syrac Ordinance and check out some of the results.
FYI, it seems they are out of business, again.

 

[ed308]

I've got a AR10 coming form Aero but supplying the 22" 6.5 Creedmoor barrel from ARP. Hoping I don't need an adjustable gas block. Aero doesn't sell or offer them on their website either. So not sure it's needed.

 

[sucker76]

Syrac would have been a top choice but I can't find that they make a 0.875" block.

I have been leaning towards the Superlative arms AGB.

 

[smittyb]

I think you might have trouble finding any Syrac still in stock.
I forgot to mention, another reason I like the SLR is it has spring detent clicks. This makes repeatable adjustments easy.
http://slrrifleworks.com/index.php?route=product/product&path=57_103_168_82&product_id=372

 

[sucker76]

I think you might have trouble finding any Syrac still in stock.
I forgot to mention, another reason I like the SLR is it has spring detent clicks. This makes repeatable adjustments easy.
http://slrrifleworks.com/index.php?route=product/product&path=57_103_168_82&product_id=372

Noted, thanks