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- Standard gas block, where all gas is vented back
- Restrictive gas block, where extra gas is vented forward through the barrel
- Patented “bleed off” gas block, where extra gas is bled off from the gas block
Best Adjustable Gas Block
$89
at OpticsPlanet
Prices accurate at time of writing
Prices accurate at time of writing
Available Coupons
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25% off all OAKLEY products – OAKLEY25
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Gas Block Review
If you haven’t checked out our Guide to AR-15’s, check that out first, but here’s the gist on gas blocks. Gas blocks take some of the gas behind the bullet to use it to push back the BCG so it can eject the spent brass, strip another round, and reset the hammer. It’s what makes the AR-15 semi-automatic instead of bolt-action. You can see it on top of the barrel at the right side of the GIF.
3-In-1 Gas Block
Regular Adjustable Gas Block
From 0 to 4.5 turns, you restrict the flow of gas, which is what all the other adjustable gas blocks do. This extra gas is sent forward out the barrel. You can see with this model from Michael Bell, the turns open up the hole for gas to vent back towards the BCG. Less gas = less recoil.
Regular Non-Adjustable Gas Block
At 4.5 turns, the gas port is fully open and acts as a normal non-adjustable gas block. This is what you would use if you want maximum reliability with a little extra recoil.Bleed Off Gas Block
This is where Superlative Arms shines…instead of restricting the hole and letting the gas go out the muzzle, an extra area opens up where the gas can “bleed off” from the gas block itself.
Bleed Off…Who Cares?
I think there’s two groups of people who will really get the best benefit out of the Superlative.Those with Suppressors
Having that extra gas go forward means it is going through your suppressor…and that means increased blowback on yourself and extra crud in your gun. Bleeding off the gas will decrease the blowback and reduce a lot of the carbon that will gum up your action.
- Will velocity be negatively affected since extra gas is being bled off?
- Is there excess sound since gas is being bled off from the gas block?
Those with Pencil Barrels
I don’t fall in the suppressor category (yet!) but I first found out about Superlative when I wanted to build a pencil barrel (.625″ compared to the normal .750″) from Ballistic Advantage and couldn’t find an adjustable gas block for that size.
Other Stuff
If you don’t fall into those categories, there’s still some awesome stuff about the Superlative that might still make it worth it.
Conclusion
Best Adjustable Gas Block
$89
at OpticsPlanet
Prices accurate at time of writing
Prices accurate at time of writing
Available Coupons
-
25% off all OAKLEY products – OAKLEY25
Copied! Visit Merchant
41 Leave a Reply
How does the bleed off effect velocity? is it lower because pressue is vented through the block verses the restricted mode?
so far as blow back (smoke) in videos. i noticed restricted setting that smoke jettisoned rearward and upward from port notably. with bleed off setting less smoke drifted upward from port in lesser amount with less propulsion also a smaller amount of smoke forward of gas block. so i personally saw a very noticeable difference.
so far as sound the real difference i saw and heard wasnt so much the sound but rate of fire was much faster cadence in restricted mode. so id expect if start to finish mag dump would be faster times for restricted. which makes sense to me. at any rate, this does not matter much if operating in semi automatic mode. just my two cents. good review however! thanks! Douglas
What is not good about this review is the lack of mention of gas block diameters. If you have a .875 barrel and get this block in that size you will need over .9255 inches of space above the gas block centerline to free float the block under a Handguard. Good luck finding one with that amount of space as I can't. The only option is a shortened guard and an exposed gas block.
Check out SLR Rifle works gas blocks
Can anyone tell me if the Supperlative Arms adjustable Gas block with bleed off is a “low profile gas block”? I have determined that it is the best adjustable gas block and therefor want to use it on my current build, but I need a low profile block to fit under my slim handgaurd. Does anyone happen to know if this is a low profile or not? Thanks!
I just ordered one from midwayusa for my LR-308 build the description says low profile.
SLR Rifleworks does
The SA adjustable GBs, both for DI and their aftermarket piston kits, all fit underneath the Midwest Industries fore end model MI-G4M in various lengths. I have used their model G3 with the SA adjustable blocks installed with their piston kits. The DI adjustable block is slightly taller, but the MI G4 has plenty of room down the top rail cutout. I like the SA adjustable models because it allows for the removal of the Op Rod without removing the gas block or the fore arm. Not a consideration for DI methods. One further thing I like about the MI fore arms is, the included barrel nut is designed so that gas tube or op rod timing is no consideration. There are no barrel nut thru holes. Torque barrel nut to spec and be done. Nice!
Do you find it difficult to live up to your last name?
Some have complained having issues on their AR's with this gas block, but I've used this on my .308 AR-10 and love it. I've had it on it for about 4 months with more than 300 rounds through it with no problem. I only shoot it suppressed, but have found that I can dial in the bleed off to have much less felt recoil and less gas in the face, while still fully cycling and getting bolt lock back after the last round. I'm a big fan.
I have a .308 build with a midlength government profile barrel, first time shooting with this gas block and in restricted mode the BCG will not unlock from the chamber and had to be leveraged back in order to unlock. I also experienced alot of inconsistancy with it, once I started opening it up enough to get BCG cycleing I would adjust it until I got the bolt to lock to the rear and then would have FTE, FTF issues, adjusted a little more and resolved that only to lose the bolt locking to the rear on an empty magazine. I was never able to acheive consistant bolt cycleing and empty magazine rear lock.
Anyone having issues running a ar 10 308 with the bleed off mode? I have a 308 and 223 unsuppressed and works great with the 223. With the 308 I have been to the range 4 times and have had problems from fte to ftf to bolt not closing after tuning. Finally gave up and went to restrictive mode and so far my last 40 rounds no issue with 2 inch groups at 200 yards. Both rifles ar aero with jp lmos and capture springs with BA barrels and SA gas blocks. Also both have Vortec viper scopes. Again any one else having issues with their 308?
The author mentioned the benefits for suppresed rifle but never detailed the benefits for pencil barreled (.625) rifle.
Wondering this as well
Would the bleed off from an appropriately tuned adjustable gas block decrease the excess gas enough to allow for use of a muzzle brake without disturbing nearby shooters from concussion or noise?
Statement in this article: "Bleeding off the gas will decrease the blowback and reduce a lot of the carbon that will gum up your action." Then why not bleed off more gas to reduce more carbon and blowback? Why not bleed off all the gas and eliminate ALL blowback and carbon? The "bleed off" model does not make sense. You WANT the gas to go out the end of the barrel, except for just enough to cycle the bolt.
I’m actually wondering the same although I like the design and I’m fact just acquired one. Trying to see if it’s better Than my other....
they’re mainly for suppressor and non suppressor shooting...
There has to be some other reasons to back up bleeding out gas from the block vs just restricting to what’s needed which generally does the same thing and eliminates having to do extra cleaning under the handguard??
A) reduce gas pressure by letting some gas bleed out of the block
Vs
B) reduce gas pressure by restricting gas inlet
only Pro for A I can think of is eliminating carbon build up in the gas block itself which is understandable I guess... although my other gas block design gave me no troubles as of yet. ... am missing something?
You guys are over thinking this. You are failing to understand the adjustable function of this gas block. The way this block is reducing the amount of gas (thus, amount of force) is through the bleed off. If all of the gas were exiting through the barrel, then there would be no reduction in gas/force. If you want all the gas to go out the front of your barrel, then don't get an adjustable gas block lol. Do you want to be able to fine tune the amount of force exerted on the BCG? Great! Then get an adjustable gas block. Do you want all the gas to go out the front of your barrel? Great, get a fixed gas block.
Do you want to be able to fine tune the amount of force exerted on the BCG? Great! Then get an adjustable gas block. Do you want all the gas to go out the front of your barrel? Great, get a fixed gas block. You can't have it both ways, that's not how physics works man. The bleed off model is LITERALLY what is allowing you to cycle the bolt with the minimum amount of gas. How else do you think an adjustable gas block works? What exactly do you think is being ADJUSTED?
So i recently bought a new B.S.F. 18in 223 wylde barrel and got the SA gas block to go along with it, but I am just discovering that the new .875 OD of the barrel and the the block on top of that wont fit into my Aero Atlas S-One hand guard. So i was Curious if any one has had a similar issue and has any suggestions on handgaurds that would fit properly?
SLR HELIX HAND GUARD WILL DO THE TRICK.
If you could actually keep any in stock for sale.
How many inch pounds do you torque the superlative with set screw option?
If you mean the clamp on one, No more then 34
Is the "bleed-off" feature on at all times, or is it only on when the gas block is completely open?
You have the option. With the screw all the way in, it’s in restriction mode, as you screw it out, gas is allowed down the gas tube. If you screw it out 4.5 turns it’s in full open. As you continue to screw it out it enters bleed-off mode, the more you screw it out, the more gas gets bleed off
I built an 80% .308 running a Vseven titanium bcg and lite weight 16"barrel. Decided to go with Superlative Adjustable GB for the adjustability but also for its "bleed off" mode. Using that, I figure to gain either less actual recoil than the restrictive mode, or a more "conditioned" less-felt recoil. I have found that when using bleed off mode, the barrel gas port size must be considered because if that is anything smaller than .070, or maybe even .072, you will have to unscrew the adjuster out (CC) quite a few turns to get bolt to lock back. I believe my port size came factory 'tuned' to the weight of the bcg and at .068, I never got the bolt lo lock up at around 10-12 turns out, when I experienced other problems of a FTFeed nature. Anybody experienced this or anything similar with the .308 carbine? What about 80% lowers not holding the magazine up into the magwell high enough to feed easily?
I've got a .750" dia.clamp on model on back order for about a month thru Brownells. I'm building a 22 Nosler and it's recommended one use an adjustable gas block for the increased gas pressure of the 22 Nosler caliber. Ballistic Advantage barrel should arrive this week. Would be nice if the gas block were to show up too!
Seeing as it has been exactly a year for this article, I'd be interested in knowing if the opinion of the author still stands and how the block has held up if he's still using it. I just put one of these on a new 308 build and I'm itching to take it out and run through the break-in procedure for the barrel using it! Thanks for the review!
Looking to add a adjustable gas block to my AR-10 / .308 build. Any additional pros/cons using Superlative on this platform?
As long as you match up the diameter and use the appropriate gas tube (some need to be higher due to the higher receiver), it should do well.
I'm considering building an AR Pistol with the suppressor under the hand guard. In this case, my grip may be over the suppressor (above/forward the gas block). My suspicion is that the bleed off could easily create a zone where you would not want your hand.
Would love to hear from somebody who can confirm this?
I have one on a Faxon 14.5" pencil barrel that I use in competition. And it works great!
I really noticed the exhausted blow by when shooting dirty military ammo at a casual shooting event. 100 rounds an my support hand was black with soot. Not nearly as noticeable using factory or my reloads. I'm not sure it it is because the surplus ammo is a higher pressure load or if it is just dirtier (which it is).
How is it possible to adjust that gas block with a hand guard over it? Really long allen wrench? Do you need a certain make of hand guard?
Yup, you'll either need a long allen wrench (it comes with one), have a handguard with lots of slots in it, or take off the handguard.
Did anybody else notice the bleed off system had a slower rate of fire than the restricted system? Along with a quieter shot!?
And you can visually watch him have a harder time with the restrictive system apposed to the bleed off.
Pinned > set screw > clamp
The review did not cover some of the specifics. The bleed off setting cost a 2fps loss over his traditional gas block. The restricted setting gained him 70fps over the traditional gas block. Both traditional blocks and bleed off settings performed very closely together. Bleed off settings perform better with suppressor due to decreased blowback sound while restricted performs better for general use by gained velocity by retaining energy in the barrel. Both settings of the adjustable gas block decrease felt recoil caused by over gassing of the ar15. This is a great product and can't wait to install mine. AGB are fueling a new trend in AR15s where people are using lower weight components, BCGs and buffer weights, to reduce the mass that reciprocates during the cycle to promote higher competitive performance.
Thanks for adding that in Matt!
An interesting point, however, is that Bell recognized that using the SA gas block would be of marginal benefit to a DI system. He concluded that the block is best with a piston system....which I want but cannot afford.
If this gas block was a little less expensive, I would give it a go. Please do a follow up review though so I can see how it stands up over time.
Thanks for your efforts.