Superlative Arms Gas Block Review

Who makes the best adjustable gas block on the market right now?

Superlative Arms that’s who!

Superlative Arms Gas Block, Rainier Arms
Superlative Arms Gas Block, Rainier Arms

Easy stuff…they’ve got two colors, two install methods (set screw + clamp), and all the sizes you might need.

The cool stuff?  It functions as three different types of gas blocks:

  • 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

Don’t worry…I’ll explain everything in detail and go over why it’s the best choice for pencil barrels, suppressor users, and anyone else tired of regular gas blocks.

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.

Direct Impingement
Direct Impingement

The thing is…there’s usually excess gas that moves back so you can account for weak ammo or some dirtiness in the system.  This excess gas adds felt recoil since it sends the BCG back with extra force.

Enter…the adjustable gas block.

The adjustable gas block restricts the size of the hole that allows gas to move back towards the BCG.  This way you can tune your gas block to release the least amount of gas for your combo of rifle and ammo.

There’s a bunch of these as you can see in our Best AR-15 Upgrades article.

So what does Superlative Arms’ adjustable gas block ($89) do differently?

3-In-1 Gas Block

Superlative Gas Block
Superlative Gas Block

By turning the screw which has some nice clicks, you can choose the best kind of gas block performance you need.

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.

Superlative Arms 0 to 4.5 Turns
Superlative Arms 0 to 4.5 Turns

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.

Superlative Arms Bleed Off
Superlative Arms Bleed Off

The area is next to the adjustment screw and vents the extra gas forward.

Superlative Gas Block Bleed Off Hole
Superlative Gas Block Bleed Off Hole

So it accomplishes the same recoil reduction but doesn’t send gas out through the barrel.

And yes…it works!  As evidenced from my competition upper build with the Superlative.

Superlative Arms Gas Block Bleedoff
Superlative Arms Gas Block Bleed Off

But I know what you’re asking yourself…

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.

Superlative Arms Full Auto Suppressor
Superlative Arms Full Auto Suppressor

Two possible questions come up and are answered by Michael Bell again.

  1. Will velocity be negatively affected since extra gas is being bled off?
  2. Is there excess sound since gas is being bled off from the gas block?

He answers those two questions in his field review.

TLDW:  Yes, slightly.  No, actually a decrease of ~8dB.

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.

Superlative Arms Gas Block .625 Clamp
Superlative Arms Gas Block .625 Clamp

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.

Superlative Arms Gas Block Weight
Superlative Arms Gas Block Weight

The main thing is that turning screw does not do the actual blocking of the gas port.

I’ve found with other adjustable gas blocks (like my old go-to Seekins, $57) that the carbon seizes up the screw after a couple hundred shots.

True…you aren’t going to be adjusting on the fly that much, but it was pretty annoying to have to take the hand guard off to muscle the screw.

Installing Superlative Arms Gas Block
Installing Superlative Arms Gas Block

Other stuff…it’s pretty light as evidenced above, there’s two colors, there’s a mechanism that prevents you from backing out the screw too much, and you have the choice of set screw or clamp.

My opinion…if you don’t have set screw dimples already, go with the clamp.  It’s the most solid method and evens out the force on the barrel (if you’re using a torque wrench…which you should).

Conclusion

The Superlative Arms Adjustable Gas Block ($89) is perfect if you are running a suppressor or are using a pencil barrel.  It also offers some great stuff even if you aren’t.  If they are out of stock there, you can also check out Rainier Arms and the Superlative Arms actual site.

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8 Comments on "Superlative Arms Gas Block Review"

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Mihk
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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?

Joe
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Did anybody else notice the bleed off system had a slower rate of fire than the restricted system? Along with a quieter shot!?

Joe
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And you can visually watch him have a harder time with the restrictive system apposed to the bleed off.

Brian
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Pinned > set screw > clamp

Matt
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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.… Read more »
Mattb
Guest

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.

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