PRO2A 16" 5.56 NATO NR Side Charging Upper Kit | M-LOK Rifle Build Package

PRO2A 16" 5.56 NATO 1/7 NR Side Charging Melonite M-LOK AR-15 Upper Kit

Simplify your build process and modernize your rifle's manual controls with the PRO2A 16" 5.56 NATO Non-Reciprocating (NR) Side Charging Master Build Kit. This 100% American-made master package contains every essential component required to complete a stripped lower receiver into a high-performance, non-NFA legal rifle. Anchored by an ultra-ergonomic left-side non-reciprocating side-charging receiver system, the upper features a 16-inch hardened Melonite 4150 CMV steel barrel and a slim profile free-float M-LOK handguard. Crucially, this master bundle ships complete with a pre-headspaced matching side-charging bolt carrier group, a full mil-spec lower parts kit (LPK) with a polished fire control group, and a 6-position adjustable carbine stock extension assembly.

Key Features

All-In-One Master Rifle Package: Takes the technical guesswork out of specialized assembly. This matching master configuration ships complete with a side-charging BCG, full lower parts kit, polished fire control trigger assembly, and standard adjustable stock setup to finish a stripped lower receiver out of the box.
Non-Reciprocating Side Charger: Modern left-side operation allows you to charge the rifle or clear malfunctions quickly from the left side without losing your cheek weld or sight picture. The charging handle stays completely stationary while firing.
Advanced Melonite Barrel Protection: The heavy-duty 4150 Chrome Moly Vanadium steel barrel is fully treated with an advanced Salt Bath Melonite finish inside the bore and across the exterior to extend operational service life and maximize corrosion resistance.
Versatile 1:7 Twist Rate: Precision button-rifled twist configuration meticulously engineered to accurately stabilize standard mid-grain tactical loads up to heavy duty 62gr, 69gr, and 77gr match ammunition.
Ultra-Smooth Mid-Length Gas Dwell: Pairing a precision 16-inch barrel with a true mid-length gas tube drops internal carrier pressure, establishing an exceptionally soft recoil impulse that ensures smooth cycling and fast follow-up shots.
Slim Profile Free-Float M-LOK Rail: Machined from high-strength aluminum, the lightweight handguard isolates barrel vibrations to preserve uniform mechanical accuracy while providing a continuous top rail and extensive M-LOK modular spacing.

Technical Specifications

Upper Receiver	Gibbz Arms G4 Billet Aluminum, Non-Reciprocating Left-Side Charging Handle, Closed-Top Anti-Debris Profile, Type III Hardcoat Anodized Black Finish
Bolt Carrier Group (BCG)	Full M16 Profile, Heavy-Duty 9310 Steel Bolt Face, Nitride/Melonite Treatment, Properly Staked Gas Key, MPI Tested
Barrel Specification	Choice of Barrel: Carbine Length M4 Profile, Mid Length Govt Profile or Carbine Length CHF (Cold Hammer Forged) M4 Profile - all of them are 16 inch, 5.56 NATO Caliber, 4150 Chrome Moly Vanadium Steel, 1:7 Twist, Nitride/Melonite Treated
Caliber	5.56x45mm NATO (Fully accepts and cycles .223 Remington ammunition safely)
Twist Rate	1:7 Twist
Gas Operating System	Carbine or Mid-Length Gas, Low-Profile 4140 Steel Gas Block, Seamless Stainless Steel Gas Tube
Muzzle Device Component	Standard A2 Flash Hider with Crush Washer Pre-Installed, 1/2x28 Thread Pitch
Handguard	15 inch Slim Profile Free-Float Aluminum Handguard, Continuous Top Picatinny Alignment, Modular M-LOK Attachment Points
Lower Receiver Parts Kit	Complete Mil-Spec Spring and Pin Kit, Polished Single-Stage Hammer and Trigger Assembly, Standard A2 Pistol Grip
Stock & Buffer Extension	6-Position Adjustable M4 Carbine Buttstock, Mil-Spec Carbine Buffer Tube, Standard 3oz Carbine Buffer, and High-Tensile Buffer Spring
Manufacturing Origin	100% Assembled and Quality Checked in the USA with Pro2A Tactical Lifetime Factory Warranty

Why Buy This Product?

The PRO2A 16" 5.56 NATO Side Charging Master Kit represents the ultimate streamlined solution for builders who want specialized rifle performance without the headaches of mismatched custom components. Sourcing small lower parts, buffer springs, and bolt carriers from separate distributors often leads to stacked manufacturing tolerances. This results in failure to feed, short-cycling, or loose-fitting parts. Pro2A Tactical answers this challenge by headspacing the included side-charging bolt carrier group natively to the 16-inch Melonite barrel and tuning it alongside the matching lower component hardware, delivering complete system synergy right out of the box.

What truly sets this upper assembly apart is its mechanical design. The non-reciprocating side-charging platform modernizes your manual operations, allowing you to charge the rifle or clear malfunctions quickly from the left side without losing your cheek weld or sight picture. This closed-top design also naturally minimizes gas blowback toward your face, which is especially noticeable when firing rapidly or operating suppressed. By combining a true mid-length gas system for minimized internal carrier velocity and an aggressive 1:7 stabilization twist, this master kit delivers uncompromised accuracy and low-recoil management. Backed by a full factory lifetime warranty and built with strictly domestic components, this master conversion kit is a rock-solid tactical asset.

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