PRO2A 16" 12.7x42 (.50 Beowulf Compatible) 1/20 Carbine Length Melonite NR Side Charging M-LOK AR-15 Upper Kit

Product Overview

The PRO2A 16" 12.7x42 Carbine Length Melonite NR Side Charging M-LOK AR-15 Upper Kit delivers unparalleled ergonomic operation combined with devastating, large-caliber stopping power in a full-length shoulder rifle configuration. Chambered in the massive 12.7x42mm caliber (fully compatible with .50 Beowulf ammunition loads), this complete master build package upgrades the traditional rear operational pull tab to a premium Left-Side Non-Reciprocating (NR) Charging System. Built with a premium 16-inch 4150 CMV heavy-profile barrel, the upper assembly comes completely assembled, headspaced, and timed, alongside a type-matched side-charging profile M16 Nitride bolt carrier group, a full lower parts kit, and a 6-position adjustable carbine buttstock setup to finalize your performance project right out of the box.

Key Features

Non-Reciprocating Side Charging (NRSC) Handle: Optimizes charging ergonomics by pinning the manual lever forward while firing—preventing moving interference with support structures while allowing lightning-fast left-side cycling without lifting your head from the stock.
Complete Master Build Package: Eliminates procurement mapping variables by grouping a pre-assembled side-charge upper receiver, pre-headspaced side-charging bolt group, complete internal lower pin hardware, and a matching stock completion package.
Modified Big-Bore Upper Receiver: Engineered with an enlarged and beveled ejection port track designed explicitly to allow flawless, high-velocity extraction path clearing for wide-diameter 12.7x42mm casings.
Advanced QPQ Melonite Protection: Liquid salt-bath nitride surface treatment shields internal rifling and external steel paths against high-thermal wear, intensive moisture fouling, and mechanical pressure scores.
6-Position Adjustable Buttstock: Includes a heavy-duty adjustable stock and high-tensile receiver buffer system to balance heavy big-bore recoil impulses and ensure clean point-of-aim tracking.
Slim Free-Float M-LOK Rail: Isolates structural barrel harmonic variables to protect uniform grouping accuracy while establishing continuous top Picatinny rail alignment and modular side mounting real estate.

Technical Specifications

Charging System Style	Left-Side Non-Reciprocating (NR) Side-Charging Upper Assembly; Forward Handle Remains Stationary While Firing
Upper Receiver	Gibbz Arms G4 Billet Aluminum, Custom-Enlarged Ejection Port for Big-Bore Brass Clearance, Type III Hardcoat Anodized Matte Black Finish
Bolt Carrier Group (BCG)	M16Profile, Heavy-Duty Carrier, 9310 Steel Bolt, Slick QPQ Black Nitride Treatment, MPI Inspected, Properly Configured Staked Gas Key Layout
Barrel Length & Contour	16 Inches; Heavy Contour Profile Axis
Barrel Material Composition	4150 Chrome Moly Vanadium (CMV) Steel
Twist Rate	1:20 Twist (Precision-engineered to stabilize heavy large-diameter loads smoothly)
Barrel Lining Coating	QPQ Melonite / Liquid Salt Bath Nitride Interior Bore and Exterior Finish for Maximum Erosion Resistance
Gas Operating Loop	Carbine-Length Gas System, High-Tensile Stainless Steel Gas Tube
Muzzle Thread Pitch & Device	49/64x20 TPI (Thread Pitch Layout); Equipped with Competition Muzzle Brake
Handguard Rails Profile	15 Inch Slim Profile Free-Float Aluminum Handguard, Integrated Top Picatinny Rail Alignment, Matrixed M-LOK Structural Slots
Lower Receiver Parts Kit (LPK)	Complete Mil-Spec Internal Hardware Small Components (Springs, Detents, Selector Pins), Single-Stage Fire Control Group Assembly (Trigger, Hammer, Disconnector), and Standard Mil-Spec A2 Pistol Grip
Buttstock Assembly Setup	6-Position Adjustable M4 Buttstock, Mil-Spec Diameter Receiver Extension Tube, 3oz Carbine Buffer, and High-Tensile Recoil Buffer Spring Group
Manufacturing Origin & Quality	100% Proudly Assembled, Timed, and Headspaced in the USA backed by Pro2A Tactical Lifetime Factory Warranty Program

Why Choose the PRO2A Non-Reciprocating Side-Charging 12.7x42 Rifle Kit?

Harnessing a thumping .50 caliber straight-walled cartridge inside an AR-15 platform demands precision engineering from the bolt lugs to the receiver frame. Standard rifle receivers cause catastrophic stovepipe malfunctions and failure-to-extract errors because narrow mil-spec ejection openings cannot clear wide straight-walled brass. Pro2A Tactical eliminates this engineering barrier directly on the manufacturing line—utilizing custom-expanded ejection channel tracks paired with a matching, pre-headspaced side-charging 9310 steel bolt face to guarantee consistent extraction strings. By moving the cycle layout to a left-side ergonomic handle, you can clear chamber actions or load heavy rounds intuitively while keeping your eyes completely downrange, overcoming the awkward clearance issues of large optics and standard charging latches. By aligning an ultra-hard 16" Melonite heavy barrel to an integrated lower component setup and 6-position adjustable buttstock, this master build kit delivers a cycle-tuned, unified shooting ecosystem designed for absolute large-bore reliability.