Home Forums Hunting & Shooting AR and Tactical Rifles Your favorite adjustable gas block

Replacing front sight and using a free-floating forearm on my Colt 6920 Carbine. What gas block do you guys like for this application?

I've had SLR and Syrac, the two best. Both work well, flip a coin. SLR has top notch customer service, never delt with Syrac.

I run SLR and love them.

SLR

Syrac. Never used an SLR, what's that funky lever on the side?

It's a leaf spring, not a lever.

I have two SLR's and like them.

I have only ever used SLR's when the gun really needed it. Is your rifle really overgassed? Where do the fired brass eject to? Most low to mid end AR's are to some extent overgassed to ensure function with all factory ammo.

True the extra gas in theory is harder on the gun but most folks will never shoot it enough to wear the parts out anyways. The adjustable gas block really comes into its own for guys who want to tune the gun to specific loads, guys who shoot suppressed or guys shooting competitions where speed from shot to shot matters as the overgassing causes the muzzle to dive down off target.

Its up to the end user but unless my rifle was really overgassed, had ejection issues or i was planning to shoot it suppressed with subsonics then any reasonable low profile fixed gas block would likely work just fine for 95% of users.

Good to know. Thank you. I just thought if I was changing the gas block anyway, might make sense to make it adjustable.

I wouldn't put one on a 223/5.56 unless it really needed one. Changing buffer weights has always worked for me with the AR-15 in .223/5.56. From what I have experienced and what seems to be the case for many people, adjustable gas blocks are best used on non standard calibers, so the gas system can be tuned or tamed. Not all cartridges work well with the .223 gas system. However, rather than make them right from the get go, manufacturers decided to let the end user retro fit a adjustable gas block rather than properly gas the barrel in the first place.

An adjustable gas block makes a smoother shooting Gun. IMO

Since it's been stated that an adjustable gas block is not always needed, save your money and just cut down the original FSB. You'll end up with a pinned low profile gas block that costs you nothing but a little time and will never come loose.

I've never used or needed an adjustable gas block and think they are simply a fad that has been passed on by people reading the internet rather than actual shooting experience.

That may be true for the many people, not all. They do work and do solve issues that some manufacturers refuse to address.

Refusing to listen to good advice and buying over gassed junk doesn't count...

Am I the only one who sees the irony here?

Of my 6 AR's only 3 are factory builds, mommas Troy and my 2 Northtechs and all were built right from the factory so none of them have gas issues.

For a blaster or HD gun a little overgas isnt bad as it ensures cycling and most will benefit from a bit heavier buffer. $50ish for a buffer and low profile gas block or $100 for an adjustable, its all user preference.

For an uber accurate or hunting gun the extra bit of smoothness from the adjustable is indeed nice and is what i use for my heavy 20" side charge build but its all high end parts so i took the plunge for adjustable.

My experience overall agrees with Wareagle that for most 5.56's users they aren't needed. Non 5.56, or suppressed they can be beneficial as well as for those users who want to tune their 5.56 to 1 particular load.

If money is any concern and assuming its installed correctly so as to not impede gas flow almost any gas block will work for less money.

That said i would never tell a man what to do with his money and i understand want, just pointing out its likely not a need on a 5.56.

I'm with you

To me it's just nice to have the option. Kind of like buying a fully loaded Cadillac and don't put power windows on it you don't need them but it sure is nice.

No irony just Poorly worded. I've shot at least 2 guns with adjustable blocks, cuzz has 2. I have never used on in a build and the OP won't need one on his 6920.

More later.

I thought he asked for your favorite gas block? Did I miss something?

Tell me more about my over gassed junk. Oh and tell JP, Noveske, and LaRue about theirs also. I'm sure they would like to know it's just a fad.

I haven't found the need for an adjustable gas block on .223's. However, other AR variants, especially the large frame .308's, 6.5's, and 6mm's, an adjustable gas block is almost mandatory for reliable function with the use of a suppressor.

Adjustable gas blocks can be had for $30-$50 now; the days of having to spend $100+ for one are gone.

For the OP - I have used a bunch of these on different rifles; they aren't fancy, and don't have click adjustments, but do what they're supposed to and stay set once adjusted. JoeBob has them for $30, Midway has the same thing under a different name for $45. These adjust from the side.
JBO ADJUSTABLE Low Profile Gas Block .750 Black

Parallax Tactical also has some decent low priced gas blocks; I haven't used their .750 block but was very happy with their lightweight .625 adjustable block for $40. It adjusts from the front, if you prefer that.

Also - I have had beneficial results using adjustable blocks even on 5.56 barrels. They tend to be gassed for the cheapest crap ammo out there, so people don't complain about them not working. I don't shoot that stuff, so I adjust the gas down a bit for the loads I use. Overgassed barrels aren't helpful for accuracy.

If a heavier buffer helps, adjusting the gas down will help too.

I didn't know you had overpriced junk, sorry to hear that. I was referring to BM, dpms and the like which are known to be over gassed but I think you pointed it out, that's because they need to function on low powered ammo that most of those buyers tend to shoot. Whatever...

I do own or have had dealings with barrels from Noveske, LaRue, Krieger, Douglas, Shilen, dpms, BM, RR, Colt, DTECH, Olympic, AR Precision and probably a few others that slip my mind. The factory "hobby" barrels are somewhat over gassed for reasons stated above but I don't see casual gunners breaking bolts or blowing them up. The custom barrels were gassed right for the most part but let's talk about Noveske and LaRue.

I've only had 3 Noveske barrels, 2 16's and 1 18" all in 5.56 with mid length and intermediate gas systems respectively. Most would not notice any difference with an adjustable gas block on the 3 I had. Doesn't the switchblock made by Noveske just shut the gas off or on for suppressor use? I haven't seen them recommend adjustable but haven't dealt with them in a while.

My LaRue is a tad over gassed ejects at 3:00 but nothing an H2 buffer wouldn't take care of. It really runs fine with it's H buffer. They don't offer an adjustable block do they? The one they sold with mine certainly is not.

Let's get back to the OP, his Colt 6920 would benefit more by cutting down the pinned FSB than by using an adjustable gas block. I didn't say anything until someone else brought it up that he didn't need it and he changed his mind about one. A good example of everyone recommending something he didn't need simply because it's the popular thing to do now. Yes he did ask which block do you recommend he should've added and why.

But for a game gun with minimal recoil, the adjustable gas block is one part of a system. What else does JP sell for that, a low mass carrier, buffer and spring, brake? The cost isn't cheap.

Now on to calibers other than 223/5.56, I've only dealt with 17 Rem, 204 Ruger, 223AI, 223 WSSM, 25 WSSM and 22 DTI. I have friends with others but haven't messed with them though none have told me they needed anything adjustable. I did have a 308 Armalite back in the day and that's one that could've benefited with one rather than using one of Slash's heavy buffers.

As I mentioned my cousin has at least a couple of adjustable blocks on some of his wildcats and I have shot them so where's the irony especially given the OP's 5.56 Colt 6920?

I'm not saying they don't work just not every gun out there needs one, nor would every shooter benefit from one.

So now that I've pissed off the entire western world, I'll go back under my rock.

How would you know if you never tried tuning the gas? Did they run better with heavier buffers?

It's not about breaking parts. It's about tuning the gun to shoot better, exactly like adding heavier buffers.

It's funny to see a guy who's never used them telling everyone else they're no good and just a fad.

You really need to study up on reading comprehension.

TWR, your right about :

"I'm not saying they don't work, just not every gun out there needs one, nor would every shooter benefit from one."

That should have followed up our comment about the "fad for people with no shooting experience" and I don't think anyone would have questioned you. In the OP's case, an adjustable gas block isn't something I would recommend. However, if he wants one, SLR or Syrac are the way to go.

I think there's a few things going on in these threads about adjustable gas blocks that get all mixed up between the different people posting....

Some guns need an adjustable gas block.
-The cheaper guns can benefit from them, but I'd be hesitant to put good money on a bad gun.
-Suppressed guns can benefit from them.
-Odd calibers, especially the bigger stuff, seem to really benefit from them.

Some shooters need an adjustable gas block.
-If you really want to shoot as quickly as possible, an adjustable gas block is going to be needed at some point. But in my experience, that point is far, far, further down the line than what most people think. And it's part of a system. Without low mass carriers and lighter buffers and lower powered ammunition, you'll never get the real benefit of an adjustable gas block. And until you're ready to make that giant leap there are better ways to spend your money.

Some shooters want an adjustable gas block.
-If you just want one, go for it. Life is short, have fun.
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I think sometimes we start arguing about these things because somebody who WANTS one gets a response meant for somebody who thinks they, or their gun, NEED one.