Adjustable Gas Block?

[kbarnes12]

I have an AA upper and 20" barrel and bolt with a rifle length gas system on order but I am trying to decide on a gas block. I plan on shooting 100gr - 130gr bullets. Do I need an adjustable gas block? Could it be tuned to reduce recoil?

Thanks for your input.

[RangerRick]

You don't have to have one but they are nice, particularly if you reload. It will save a lot of wear on your brass.

Mine tended to unlock the bolt while pressure was still pretty high in the barrel. That made for a hard ejection and very dirty brass.

I shoot bullets of 100 grains up to 130 grains without readjusting the gas block in a 20 inch barrel.

I adjusted mine with 123 grain bullets so that it reliably ejects and locks the bolt back.

I was surprised to find that I needed to open it up more for 100 grain bullets. So be sure and test it with all the bullet weights you want to shoot.

RR

[kbarnes12]

Thanks Rick. It sounds like you have pretty much the set up I am thinking about going with. Let me ask you this, what handguards did you with? I am still trying to decide whether to go with standard rifle length and leave the gas block exposed, or to go with the extended rifle length and cover the gas block.

Also any opinions out there on the Syrac adjustable gas block? I like the idea of having the detent instead of using locktite on the adjustment screw.

[outbreaker]

I would not build one without it. Every grendel I have seen is over gassed (read tries to unlock to early like the post above). I believe this is why people bust bolts. That is my opinion.......and you know what those are like.

[txgunner00]

I would not build one without it. Every grendel I have seen is over gassed (read tries to unlock to early like the post above). I believe this is why people bust bolts. That is my opinion.......and you know what those are like.

Hello and welcome!

I agree. They are money well spent on a Grendel IMO.

[Drifter]

I haven't seen a real need on builds with rifle-length gas systems, but adjustability is definitely recommended on most midlengths.

[Chato308]

Has anyone tried the paladin machine 3 position gas block? I was wanting a 3 position block for when I get my suppressor

[Drifter]

Yes, but not with a suppressor.

They can make it to fit your needs, but the finish isn't as good as something like a Noveske switchblock.

http://secure.adpay.com/clicknbuy.aspx?itemid=2541516&p=2079&st=1

[RangerRick]

Thanks Rick. It sounds like you have pretty much the set up I am thinking about going with. Let me ask you this, what handguards did you with? I am still trying to decide whether to go with standard rifle length and leave the gas block exposed, or to go with the extended rifle length and cover the gas block.

Also any opinions out there on the Syrac adjustable gas block? I like the idea of having the detent instead of using locktite on the adjustment screw.

I have the Daniel Defense Light Rail.


I had a flip up front sight on the old gas block that I really liked that I wanted to keep, so I tried one of the gas tubes with an adjuster on it. It didn't work out. I had two and both started leaking after about 50 rounds.

I figured with all the holes in the DD rail I'd be able to get at the adjustment. No dice. I ended up drilling out a larger hole to get to it, then ended up trashing the adjustable gas tube anyway.

There's no way to tell if you can get to the side adjusters with your rail unless somebody else has the exact same setup and you know it will work.

I haven't used the Syrac, but with it's front adjustment you should be able to get at it with about any floating hand guard, unless you get a very long one.

I have a JP with the adjustment on the side and the DD rail doesn't cover it up. Just has the Allen screw, but I rarely adjust it once it's set.

I prefer the clamp at the bottom type blocks (split bottom). They just seem more secure to me, and they are easier to put on. Keeping them lined up as you tighten is a little harder, but not much.


RR

[Bwild97]

I have a PRI Adjustable gas block. It came with a rifle length, strait gas tube. I have a rifle length hand guard and I can easily get to the adjustment on its side.

[txgunner00]

Has anyone tried the paladin machine 3 position gas block? I was wanting a 3 position block for when I get my suppressor

I have one on my 10" 5.56 upper and it's OK. The owner is a good guy and will customize the block (port sizes) to your needs. I need to take mine apart and measure the ports though. They may have burned out some already as the upper seems to be getting over gassed. I'm not sure of the hardness of the material he is using or if he's heat treating them. If in fact it has burned out I feel it should have lasted longer, however this is on a short barrel that I shoot suppressed 90% of the time. Pretty cheap and easy fix though- only need to replace the cylinder that has the ports in it. Just hadn't taken the time to dig into it.

[Chato308]

I have one on my 10" 5.56 upper and it's OK. The owner is a good guy and will customize the block (port sizes) to your needs. I need to take mine apart and measure the ports though. They may have burned out some already as the upper seems to be getting over gassed. I'm not sure of the hardness of the material he is using or if he's heat treating them. If in fact it has burned out I feel it should have lasted longer, however this is on a short barrel that I shoot suppressed 90% of the time. Pretty cheap and easy fix though- only need to replace the cylinder that has the ports in it. Just hadn't taken the time to dig into it.

the gas port on my mid-length measures ~.078 but I'm not exactly sure what suppressed setting to go with?

[txgunner00]

the gas port on my mid-length measures ~.078 but I'm not exactly sure what suppressed setting to go with?

Start small and drill or ream it out until it functions reliably. I started with .050 and ended up somewhere around .064 on my .223 IIRC. I have a series of small chucking reamers specifically for this purpose because they are much less likely to break than drills and they leave a better finish in the hole. You can get them at several on-line machine tool dealers for a few dollars a piece.

[Tailgate]

For accuracy, get a low-pro adjustable gas block that CLAMPS on...not one that has a set screw(s). There are a few out there. I believe the aforementioned Syrac is one of them.

[txgunner00]

Just curious- how does clamp vs set screw affect accuracy?