AT3™ FF-ML 16 Inch .300 BLK Complete AR 15 Upper – .300 AAC Blackout 16 Inch Ballistic Advantage Barrel – 15″ M-LOK Free Float Handguard
The AT3 16″ .300 BLK Rifle Upper with SPEAR M-LOK 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 Ballistic Advantage 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 up to 20% off vs purchasing the components separately.
This fully assembled AR-15 complete upper includes:
16″ Ballistic Advantage 1:7 4150 CMV M4 Nitride Barrel (with low profile gas block & pistol gas tube)
Ballistic Advantage Modern Series barrels feature precision-machined 4150 CMV steel, durable QPQ (Nitride) coating, and a Sub-MOA accuracy guarantee.
Unique slim and lightweight design with M-LOK attachment points. Rock-solid 6061 aircraft aluminum handguard that withstands the harshest treatment. 5-slot M-LOK-to-Picatinny rail section included
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.
KAK Industry Flash Can
One of the most popular muzzle devices for AR15 pistols. The conical shape directs muzzle blast and noise directly in front of the shooter, reducing concussion for the shooter. The flash can is only 1.2″ in diameter, and can hold up to recoil without the need for a crush washer or timing.
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.
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.
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: 26″
- Gas System: Pistol
- Barrel Profile: DRP (Distinct Rigid Pattern)
- Twist Rate: 1:7
- Barrel Steel: 4150 Chrome Moly Vanadium
- Barrel Finish: QPQ Corrosion Resistant (Nitride)
- Chamber: .300 AAC Blackout
- Muzzle Thread: 5/8×24
- Barrel Extension: M4
- Diameter at Gas Block: .750″
- Gas Block Type: Low-profile
- Receiver Material: Billet 6061-T6 Aluminum
- 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
- 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. AT3 uppers are built using barrels from top brands like Ballistic Advantage and Faxon Firearms, for excellent performance and accuracy.
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.
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.
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.
Won't cycle correctly. It looks like it is under gassed, not sure if gas block is aligned correctly.
AT3™ FF-ML 16 Inch .300 BLK Complete AR 15 Upper - .300 AAC Blackout 16 Inch Ballistic Advantage Barrel - 15" M-LOK Free Float Handguard
I gave 4 stars for now only because I have not many rounds through it yet. But will prob. Be a 5 star fit and finish are great so far no ftf I will buy from at3 again!
This is one of the best uppers I have ever bought, right out of the box you can tell the quality of this upper.
Thanks for sharing your feedback, Travis. We're glad you're satisfied with your purchase. Cheers!
I ordered the AT3 FF-ML 16 Inch .300 BLK Complete Upper (.300 AAC Blackout 16 Inch Ballistic Advantage Barrel - 15" M-LOK Free Float Handguard) in FDE. The upper was shipped quickly, was very well packaged, the price was excellent, and the finish is perfect. But, above all, I was most impressed with the customer service (specifically, Alvin)... He went above and beyond in terms of keeping me apprised of my order status every step of the way (from the point they received my order to the product arriving in my hands). I'll definitely be an AT3 customer for life. Thank you!
Thanks for sharing your feedback, T Green. We're glad you're satisfied with your purchase. Cheers!