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

Product Overview

The Pro2A Left Hand 16" 12.7x42 Carbine Length Upper Kit offers a full-size, hard-hitting package tailored exclusively for left-handed rifle builders. Chambered in 12.7x42mm (fully compatible with .50 Beowulf loads), this complete build group shifts traditional rear charging handle strains to highly efficient side-charging ergonomics. This all-inclusive system supplies a caliber-matched bolt carrier group, a full lower parts kit, and a stabilizing pistol blade assembly to transform a standard stripped lower into a heavy-duty, large-caliber utility weapon with optimized full-length velocity.

Key Features

All-In-One Transformation Group: Combines a premium left-eject side-charging upper assembly, big-bore BCG, complete mil-spec lower small parts kit, and a stabilizing buffer layout.
Dedicated Left-Hand Mirroring: True southpaw engineering routes hot big-bore brass to the left, keeping debris and expanding gasses entirely out of the operator's line of sight.
Non-Reciprocating Layout: Patented left-side non-reciprocating charging handle remains completely stationary while cycling, preventing mechanical optic clearance issues.
Stabilizing Blade Configuration: Includes an ergonomic polymer pistol stabilizing blade brace paired with a matched buffer tube setup for enhanced structural control.

Technical Specifications

Upper Receiver	Patented Gibbz Arms G4 Billet Aluminum Non-Reciprocating Side Charging Upper Receiver, Left Hand Ejection, Enlarged Big Bore Ejection Port, M4 Feed Ramps, Anodized Finish
Charging System	Right-Side Non-Reciprocating Charging System (Static Handle Design) for Left-Eject Configuration
Barrel Length & Profile	16-Inch Heavy Profile
Caliber	12.7x42mm (.50 Beowulf Compatible)
Twist Rate	1:20 Twist
Barrel Material & Treatment	4150 Chrome Moly Vanadium Steel, Premium Corrosion-Resistant Melonite Finish
Gas Operating Block	Carbine Length Direct Impingement, Low-Profile Steel Gas Block, Stainless Steel Gas Tube
Muzzle Thread & Device	49/64x20 Thread Pitch, High-Efficiency Competition Muzzle Brake
Handguard Rail	15" Slim Free-Float M-LOK Handguard, Machined from 6061-T6 Aluminum with Top Picatinny Rail
Bolt Carrier Group	Full Auto M16 Profile, Premium Nitride Finish, Heavy Duty Ejector & Extractor Assembly, MPI Tested
Lower Parts Kit	Full Mil-Spec Lower Parts Kit (LPK), Machined from Domestic Heat-Treated Steels (Polished Triggers & Hammer, Springs, Pins, and Grip Components Included)
Stock Assembly	6 Position Milspec Adjustable M4 Stock , Carbine Buffer Tube, Buffer Spring, and 3oz Buffer, etc.
Manufacturing Origin	100% Made in the USA with Pro2A Tactical Lifetime Factory Warranty

Who Chooses This Upper Receiver?

Big-Bore Hunting Operators

Southpaw hunters targeting large game, hogs, or bears in thick brush select this full-length setup. It keeps hot, massive .50-caliber empty casings out of their face and eyes while delivering maximum terminal stopping power out of a stable 16" platform.

Tactical Southpaw Marksmen

Shooters wanting premium ergonomic manipulation rely on the stationary side-charging system. Bypassing the awkward reach over a standard AR-15 rear charging handle allows left-handed operators to clear, charge, or check the chamber instantly without breaking their cheek weld.

AR-15 Builders Demanding Drop-In Power

Custom gunsmiths aiming to update a standard small-frame lower into an innovative, heavy-hitting utility weapon choose this complete build group. It drops right onto standard mil-spec lowers, turning empty frames into ready-to-run .50-caliber systems.