AT3™ Low Profile Steel AR-15 Gas Block + Gas Tube + Roll Pin Combo

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from$35.99

Gas Block Size: Choose gas block size

Gas Block Size

Gas Tube Length: Choose gas tube length

Gas Tube Length

Choose your options Stock and the exact price show once you pick a gas block size and gas tube length.

Free standard shipping on orders $139+ details
90-day no-hassle returns policy
Backed by the AT3 Lifetime Warranty! what it covers

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This combo includes your choice of 4 different sizes of gas blocks, your choice of 4 different gas tube lengths, and 2 roll pins.

How to purchase: Use the dropdown menus to choose your size of gas block and gas tube length. Not sure what size you need? Check out the FAQ at the bottom of this page.

About the AT3 Low Profile Steel Gas Blocks:

4 sizes available: .625″, .75″, .825″, and .936 (.75″ is the most common size, but always measure the barrel if you aren’t sure!)
Low profile design, perfect with all free float handguards
Premium steel construction (better than aluminum for withstanding extreme temperatures)
Secured using 2 set screws (screws, Allen wrench and roll pin included)
Backed by the AT3 Lifetime Warranty

About the AT3 Gas Tubes:

Premium stainless steel gas tubes, available in 4 lengths. Backed by a lifetime warranty.

Not sure what size you need? Measure the distance from the barrel shoulder to the gas port on your barrel and compare it to the chart below. (Carbine is the most common length).

Distance to port:

Pistol = 4 inches
Carbine = 7 inches
Mid = 9 inches
Rifle = 12 inches

More Details:

AT3 Gas Block Specifications:

Material: 4150 Steel, Black Finish
Length: 1″
Height: Sits 3/8″ off of the barrel (fits under all free float handguards)
Weight: 1.5-1.8oz depending on size

AT3 Gas Tube Specifications:

Material: Stainless Steel
Finish: Natural

Total Tube Length:

Pistol: 6 3/4″
Carbine: 9 3/4″
Mid-length: 11 3/4″
Rifle: 15 1/4″

Frequently asked questions:

Q: How can I tell what size of gas block I need?

A: The gas block size is based on the outside diameter of your barrel. The most common size is .75″ (this is the military standard). If you aren’t sure – use calipers to measure the diameter of the barrel, in the area where the gas block sits. Or alternatively, you can try looking up the make and model of your rifle online for more details.

Q: How do I know if this gas block will fit under my handguard?

A: Our micro gas blocks are as small as you will find on the market. They are guaranteed to work with our AT3 handguards, and they are compatible with all the other handguards out there!

Q: How do I know what size of the gas tube I need?

A: Measure the distance from the barrel shoulder to the gas port on your barrel and compare it to the list below. (Carbine is the most common length).

Distance to port:

Pistol = 4 inches
Carbine = 7 inches
Mid = 9 inches
Rifle = 12 inches

All 16 options on this page

Perfect gas tube and gas block combination for my 50 Beowulf pistol build. I'm glad I ran across this company when I needed them. Thank you so much!

This installed and worked perfectly, no issues at all. Received it within a week of placing my order! Highly recommended..

Excellent low profile gas block for my setup, installation couldnt be easier, have ran several clips thru it with no problems, priced right, high quality.

worked perfectly!!

Works as intended, no malfunctions, straightforward installation and for the price can't beat it

Easy to install and worked great with quad rail I purchased

Thanks for letting us know, Preston—we're sorry the wrong item was sent for your Low Profile Steel AR-15 Gas Block Combo; please reach out to our support team right away so we can correct this and get you the right one!

My items were as described. Very professional customer service and fast shipping. Thanks guys !

The low-profile gas block is solid and built to spec with tight tolerances. My only gripe is the set-screw attachment — I’d prefer the barrel be dimpled, which is what I ended up doing along with a bit of Rocksett, or ideally cut and pinned for long-term security. Otherwise, it performed like a champ

AT3 Tactical · Thanks, Jesse! Glad the AT3™ Low Profile Gas Block combo is solid with tight tolerances and performs great. Good call on dimpling + Rocksett for extra security—set screws work well for most, but pinning is ideal long-term. Appreciate the feedback!

A++

AT3 Tactical · Thank you for your positive feedback! We are thrilled to hear that you are satisfied with our product. It's our mission to provide high-quality products and excellent customer service. Thank you for choosing our AT3™ Low Profile Steel AR-15 Gas Block + Gas Tube + Roll Pin Combo. Have a great day!

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I have a Ruger AR-556 with a 16" barrel and I want to get your AT3™ SPEAR Free Float AR-15 Handguard 15 Inch – M-LOK. But I do not know which low profile gas block and or gas tube to get to make it work. I am guessing it would be a .750" Micro Gas Block for the gas block size and then for the gas tube length it would be rifle. But I want to be sure before I order.
Lucas · Dec 22, 2025

AT3 Support Team — Hi! You're spot on with your Ruger AR-556 (16" barrel)—it uses a carbine-length gas system with a .750" gas block journal and requires a carbine-length gas tube for proper function. Our AT3™ SPEAR 15" M-LOK handguard is fully compatible with a low-profile .750" micro gas block. Grab one of those plus a carbine gas tube, and you'll be set for a smooth install!

Backed by the AT3 Lifetime Warranty!

All AT3 Tactical Brand Products carry a lifetime warranty against manufacturer’s defects.

This includes AT3 Red Dot Sights, Handguards, Iron Sights, and any other product that carries the “AT3 Tactical” or “AT3™” name. For other brands (ex. Magpul or Troy), please refer to the manufacturer’s warranty policy.

In the event that your AT3™ product becomes unusable, we will repair or replace the product at no charge to you.

If we cannot repair your product, we will replace it with a product in perfect working order of equal or better physical condition. The warranty is fully transferable, but we may require information about the original purchase to validate the authenticity of the product.

If your product is in need of warranty service, please contact AT3 Tactical to start the process

Our contact info is available here. To expedite processing, please provide your order information and description of the defect.

Please note: The AT3 Lifetime Warranty does not cover loss, theft, intentional damage or cosmetic damage that doesn’t affect the performance of the product.

90-day no-hassle returns

The AT3 Tactical store has a 90 day no-hassle return policy for products in good condition. You can view the full details of our return policy here.

If you encounter an issue or defect with a product after 90 days of your purchase, you can refer to the manufacturer for a warranty claim. Their policies are below.