Precision Reflex Mk12 Mod-H .223/5.56 16'' Bbl Complete Uppr Rcvr Blk

The Precision Reflex Mk12 Mod-H .223/5.56 complete upper receiver is a field-proven, ready-to-run upper assembly built on a forged 7075 aluminum receiver with hard-coat anodizing for durability. This 16-inch barreled upper comes fully assembled, cleaned, and tested—no guesswork, no assembly line shortcuts. It's designed for shooters who want a compact, accurate .223/5.56 platform that doesn't compromise on capability, whether you're running drills at the range, working from a recce position, or building a versatile carbine for duty or sport.

The barrel is Douglas 416 stainless steel with a 1:7 twist and M4 feed ramps, delivering the accuracy and reliability that separates a kit gun from a real tool. A low-profile gas block with dual set screws secures the forearm without fuss, while the rifle-length rail system and dedicated recce top rail give you two levels of mounting real estate—purpose-built for pairing a primary optic with night vision or thermal up front. The included Gas Buster charging handle with military-profile latch cycles smoothly under load, and the muzzle brake (1/2 x 28 threaded) is pinned and collared for permanence.

Every upper includes a bolt carrier group, rail-mounted flip-up front and rear sights, and a matched brake/collar combo, so you're not hunting for random parts. The black finish is clean and professional. At 25 inches overall and 5.7 pounds, this upper is nimble enough for field work without feeling toy-like. Whether you're updating an existing lower or starting a fresh build, this is a no-nonsense upper that shows its work.

Key Features

• 16-inch Douglas 416 stainless barrel, 1:7 twist, M4 feed ramps
• Forged 7075 aluminum receiver, hard-coat anodized for longevity
• Dual-level rail system: rifle-length forearm plus recce top rail for primary + secondary optics
• Gas Buster charging handle with military large latch
• Low-profile gas block with dual set screws for secure mounting
• Included bolt carrier group, ready to run
• Rail-mounted flip-up front and rear sights
• Pinned and collared 1/2 x 28 AE brake
• Factory assembled, cleaned, and tested before shipment

Specifications

Frequently Asked Questions

What lower receiver is this upper compatible with?

This is a .223/5.56 AR-15 pattern complete upper receiver. It will mate with any standard AR-15 lower receiver. The upper alone does not include a lower—you'll need to source one separately or pair it with an existing lower you own.

Does this come assembled and ready to shoot?

Yes. Every upper is factory assembled, cleaned, and tested before shipment. It includes a bolt carrier group, so you only need to attach it to a compatible AR-15 lower and you're ready to run.

What's included in the box?

The upper receiver assembly includes the complete barreled receiver, bolt carrier group, Gas Buster charging handle, rail-mounted flip-up front and rear sights, and the pinned/collared AE muzzle brake with collar.

Can I mount a night vision device on this upper?

Yes. The dual-level rail system is specifically designed for this: the recce top rail and rifle-length forearm rail give you two mounting planes to position a primary optic with night vision or thermal mounted in front of it.