AT3™ FF-ML Complete Rifle AR 15 Upper – .223/5.56 16″ Ballistic Advantage Barrel – M-LOK Free Float Handguard

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AT3™ AR-15 Bolt Carrier Group -  5.56 NATO/.300 Blackout - Black Nitride

AT3™ AR-15 Bolt Carrier Group - 5.56 NATO/.300 Blackout - Black Nitride


AT3 Tactical Standard GI Charging Handle - Black


16 Inch Lightweight AT3 Upper with 15 Inch Handguard – Made to Order and Ships in 7 Days

AT3 Complete Upper assemblies are Built for Accuracy and Reliability – Guaranteed.

  • Quality Where it Counts – premium components like Faxon Firearms barrels, and AT3 Tactical’s handguards and uppers. Don’t settle for “bargain uppers” with unknown components.
  • Guaranteed Reliability– Carefully assembled before shipment, and backed by the AT3 Lifetime Warranty
  • Unbeatable Value – Unbeatable quality in the price range. Save money by bundling, and save time by letting us do the assembly!

This fully assembled AR-15 complete upper includes:

16″ Ballistic Advantage Pencil Profile 5.56 NATO Barrel (with AT3 low profile gas block & midlength gas tube)

Ballistic Advantage Middle Pencil Barrel


The Ballistic Advantage barrel we use for this assembly has a 1 in 7 twist rate, perfect for stabilizing just about any 5.56 load you can feed it. The lightweight Pencil profile offers far better handling than front-heavy “Government” profile barrels, and the Midlength gas system produces less felt recoil.

AT3 SPEAR Free Float M-LOK handguard

AT3 Tactical Spear M-LOK Handguard 15 Inch

Lightweight and tough, this unique M-LOK handguard is the best rail we offer. This rock-solid 6061 aircraft aluminum handguard that withstands the harshest treatment. 5-slot M-LOK-to-Picatinny rail section included

AT3 Tactical Slick Side 6061 T-6 Upper Receiver

Precision machined from 6061-T6 aluminum, this assembled upper is sleek, with extra material around the barrel extension for superior accuracy. It mates perfectly with our SPEAR handguard and feature M4 feedramps for reliable feeding of ammunition.

Your choice of muzzle device(choose type with dropdown menu)

Complete Upper Muzzle Devices - A2 Flash Hider, Combat Flash Hider

Learn more about these muzzle devices: A2 Flash HiderCombat Flash Hider

Top Add-Ons

AT3 Black Nitride Bolt Carrier Group

Finish your complete upper with a reliable, easy to clean Black Nitride Bolt carrier group from AT3. They feature M16 carriers, and MPI inspected bolts made from 9310 steel and properly staked grade 8 gas key screws.

Your choice of Standard GI or Extended-Latch Charging Handles from AT3


These 7075-T6 charging handles slide right into our uppers for a complete top end. Choose between a standard latch and extended latch designs to fit your needs and budget.

More info:

This product is built-to-order in our Minnesota facility. Quality takes time – please allow up to 7 days for your order to ship.

All AT3 upper assemblies come with a Lifetime Warranty – if you ever have an issue, let us know, and we’ll make it right. It’s that simple.

Don’t see the options you’re looking for? Let us quote you a custom upper – contact us now.


  • Barrel Length: 16″
  • Total Assembly Length: 24.5″
  • Gas System: Midlength
  • Barrel Profile: Pencil profile
  • Twist Rate: 1:7
  • Barrel Steel: 4150 Chrome Moly Vanadium
  • Barrel Finish: QPQ Corrosion Resistant (Nitride)
  • Chamber: 5.56 NATO
  • Muzzle Thread: 1/2-28
  • Barrel Extension: M4
  • Diameter at Gas Block: .625″
  • Gas Block Type: Low-profile
  • Receiver Material: Billet 6061-T6 Aluminum
  • Finish
    • Black: Hardcoat Anodized
    • Flat Dark Earth: H-267 Magpul® Flat Dark Earth
    • OD Green: H-232 Magpul® OD Green
    • Gray: H-188 Magpul® Stealth Grey
    • Pink: H-224 SIG™ Pink
    • Red: H-167 USMC Red
    • Burnt Bronze: H-148 Burnt Bronze
    • Tungsten: H-237 Tungsten
    • Titanium: H-170 Titanium

3 reasons why AT3 Complete Uppers are better than the rest.

1 – Quality Where it Counts

The single most important component of an accurate AR-15 is the barrel. This upper is assembled with a lightweight Ballistic Advantage barrel for excellent performance and handling.

But the quality doesn’t stop at the barrel. Our AT3 handguard and upper work together to provide superior accuracy, meaning this upper assembly offers quality without compromises.

Many of the “bargain” complete uppers on the market source their parts from the lowest bidder – at the expense of accuracy and reliable function. AT3 is committed to using only top-quality components in our upper assemblies.

2 – Guaranteed Reliability

AT3 complete uppers are assembled with strict quality controls and carefully packaged for delivery to the customer. All AT3 complete uppers offer a Lifetime Warranty – if you ever have an issue, let us know, and we’ll make it right. It’s that simple.

3 – Unbeatable Value

When you buy a complete upper, you’ll save money and parts and assembly vs purchasing the components separately. Our complete uppers are not the cheapest on the market, but they deliver unbeatable quality in the price range. We sell direct to the customer, and cut out the middle-men, to deliver the best value in AR-15 upper assemblies.

Products available on this page:

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.

Customer Reviews

Based on 9 reviews
Kenneth Dale
Great product!

A+++ quality, the FDE matches my receiver from another company perfectly.

Thank you for leaving a review for our AT3™ FF-ML Complete Rifle AR 15 Upper. We're thrilled to hear that you are impressed with the quality of our product and that it matches your receiver perfectly. We take pride in providing top-notch products and we're glad to know that we met your expectations. Thank you for choosing AT3 Tactical!


Fits like a glove, and gave new life to my very old bushmaster AR. AT3’s shipping is fast, and so far, their products are good enough to keep me coming back.

Thank you for your kind words! We are thrilled to hear that the AT3 FF-ML Complete Rifle AR 15 Upper has given new life to your old Bushmaster AR. We take pride in our fast shipping and high-quality products, and we are honored to have you as a loyal customer. Thank you for choosing AT3!

Jeff Bear
At3 ar15 upper fde

This upper is well done. I completely dismantled it to see that it was done right. Very well done quality control. No bless. Thread locker where appropriate and looks terrific. Range time tomorrow.

Damion Pool
First complete upper ever bought and it’s amazing!

I shopped for months and months, trying to find the right combination of quality, durability, aesthetics and price. This is an A+++ in my book. Took it immediately to the range after receiving it. Fired about 150 rounds that day. Nothing to crazy, but I couldn’t curb my excitement! Only issue I had was the bolt not locking back on last round. But I chalked that up due to weak .223 rounds I had in it. I honestly don’t have anything but praise to give to AT3! Thanks for the wonderful products guys. Wouldn’t mind seeing a 6.8 SPC upper in the future though.

Thanks for sharing your feedback! We're glad you're satisfied with your purchase.

Christian P.
Great build quality!

AT3 shipped the upper the next day. The build quality of the upper is amazing, especially for the money! The OD green finish is a near-perfect match to a Magpul ODG. Lightweight and feature-rich, this is a 5 out of 5 for sure.

Thanks for sharing your feedback! We're glad you're satisfied with your purchase.