AT3™ 5.56 NATO Pencil Profile 16 Inch AR-15 Barrel

SKU: AT3-556-PEN-MID-16

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16 Inch Pencil 5.56 NATO Barrel by AT3 Tactical

Upgrade your AR-15 with a 16 inch pencil barrel to improve your handling and save on weight. While the pencil profile trims the fat up front for better balance, this barrel still uses 4150 CMV steel for longevity, and a black nitride finish for corrosion resistance. This barrel uses a midlength gas system, which is smoother than M4 style rifles, which makes it even more comfortable.

This barrel uses a .625″ diameter gas block, plus a Midlength length gas tube, both of which you can snag here at a lower, bundled cost. If you’re looking to start fresh with a complete upper assembly, check out our selection of upper and handguard combos! For this barrel, we’d recommend a handguard 12 to 15 inches long to ensure shooter comfort, plus room for accessories.


  • Length: 16 Inches
  • Material: 4150 Chrome Moly Vanadium
  • Profile: Pencil
  • Finish: Black Nitride
  • Gas System Length: Midlength
  • Gas Block Journal: .625″
  • Twist Rate: 1:7 inches
  • Muzzle: 1/2×28 Threaded
  • Barrel Extension: M4 Feed ramps
  • Weight: 23 oz.

Where are these barrels made?

AT3 has partnered with Kinetic Manufacturing, a trusted OEM manufacturer for the firearm industry to produce these barrels. We have a philosophy that great parts for the AR don’t have to break the bank, and these barrels are no exception. Our lifetime warranty on these barrels applies to any defects due to workmanship. In the unlikely event you run into an issue, we will take care of you.


Caliber5.56 NATO/.223 Remington
Barrel Length16 inches
Barrel Twist Rate1:7 inches
Barrel Material4150 CMV
Muzzle Threads1/2/2028
Barrel FinishBlack Nitride
Gas Block Size.625″ Gas Block
Barrel ProfilePencil
Barrel Gas SystemMidlength
Gas Block Journal Length1.9 inches
Barrel ExtensionM4
Weight23 ounces

Have Questions About this Product?

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.

AT3 Lifetime Warranty Logo

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

This includes AT3 Red Dot SightsHandguardsIron 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.