AT3 Tactical 16" 5.56 NATO Pencil Barrel AR-15 JNL Ready Build Kit – M-LOK / Magpul CTR
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AT3 16 Inch 5.56 JNL Ready Build Kit – Pencil Barrel M-LOK Rifle Setup
Features
- Just Needs Lower kit includes an assembled 16 inch 5.56 NATO upper plus the parts needed to complete a stripped AR-15 lower receiver
- Lightweight pencil-profile barrel keeps the front end easier to handle than heavier government-profile builds
- Mid-length gas system pairs well with the 16 inch barrel for a smoother carbine setup
- Assembled upper includes AT3 billet upper receiver, SPEAR M-LOK handguard, black nitride BCG, and selected charging handle and muzzle device
- Lower build components include Magpul CTR stock, MOE pistol grip, Magpul trigger guard, buffer tube kit, lower parts kit, and AT3 enhanced Nickel Teflon trigger group
The AT3 16 inch 5.56 JNL Ready Build Kit is built for customers who want the upper receiver already assembled and only need to supply a stripped AR-15 lower receiver. This kit pairs a lightweight 16 inch pencil-barrel upper with Magpul CTR furniture and an upgraded AT3 Nickel Teflon trigger group, giving the build better handling and a cleaner trigger than a basic rifle kit.
Note: This kit includes an assembled upper receiver and lower build components. Stripped lower receiver is not included, and lower parts are not assembled. Built-to-order upper assemblies may require additional processing time before shipping.
Specifications
- Brand: AT3 Tactical
- Model: 16 inch 5.56 NATO JNL Ready Build Kit with Pencil Barrel and M-LOK Handguard
- Caliber: 5.56 NATO
- Build Type: Just Needs Lower / assembled upper with lower build components
- Upper Receiver: AT3 assembled billet upper with SPEAR M-LOK handguard
- Barrel Length: 16 inches
- Barrel Profile: Pencil profile
- Twist Rate: 1:7
- Gas System: Mid-length
- Gas Block Journal: .625 inch
- Muzzle Thread: 1/2×28
- Bolt Carrier Group: AT3 Black Nitride BCG
- Trigger: AT3 Enhanced Nickel Teflon Trigger Group
- Stock: Magpul CTR Stock
- Grip: Magpul MOE Pistol Grip
- Trigger Guard: Magpul Trigger Guard
- Buffer System: Carbine buffer tube kit
- Color Options: Black, Flat Dark Earth, OD Green
What’s Included
- 1x AT3 16 inch 5.56 NATO Complete Assembled Upper with Pencil Barrel and SPEAR M-LOK Handguard
- 1x AT3 Black Nitride Bolt Carrier Group
- 1x AT3 MIL-SPEC Charging Handle
- 1x AT3 A2 Birdcage Flash Hider
- 1x AT3 Enhanced Nickel Teflon Trigger Group
- 1x Magpul CTR Stock
- 1x Magpul MOE Pistol Grip
- 1x Magpul Trigger Guard
- 1x AT3 Buffer Tube Kit
- 1x AT3 Lower Parts Kit
All 3 options on this page
- AT3 Tactical 16" 5.56 NATO Pencil Barrel AR-15 JNL Ready Build Kit – M-LOK / Magpul CTR - Color: Black | SKU: AT3-RFL-KIT-16-0-BLK
- AT3 Tactical 16" 5.56 NATO Pencil Barrel AR-15 JNL Ready Build Kit – M-LOK / Magpul CTR - Color: Flat Dark Earth | SKU: AT3-RFL-KIT-16-0-FDE
- AT3 Tactical 16" 5.56 NATO Pencil Barrel AR-15 JNL Ready Build Kit – M-LOK / Magpul CTR - Color: OD Green | SKU: AT3-RFL-KIT-16-0-ODG
Customer reviews 7
AT3 Tactical · Thanks for sharing your feedback! We're glad you're satisfied with your purchase.
AT3 Tactical · Thanks for sharing your feedback, Chris. We're glad you're satisfied with your purchase. Cheers!
AT3 Tactical · Thanks for sharing your feedback, Jayson. We're glad you're satisfied with your purchase. Cheers!
AT3 Tactical · Thanks for sharing your feedback, Jase. We're glad you're satisfied with your purchase. Cheers!
AT3 Tactical · Thanks for sharing your feedback, Peter. We're glad you're satisfied with your purchase. Cheers!
AT3 Tactical · Thanks for sharing your feedback, Johnny. We're glad you're satisfied with your purchase. Cheers!
AT3 Tactical · Thanks for sharing your feedback, Dillan. We'll make sure to send compatible parts moving forward. If you need help with anything, please don't hesitate to reach out to us.
Questions & Answers 5
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Warranty & returns
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.











