PRO2A 20" 6.5 Grendel 1/8 Rifle Length NR Side Charging Melonite M-LOK AR-15 Upper Kit

Unlock true flat-shooting, medium-to-long range ballistic performance out of your AR-15 platform with this premium 100% American-made conversion system. The PRO2A 20" 6.5 Grendel Master Master Kit anchors a match-ready, premium Melonite-treated 4150 CMV barrel to a high-end Gibbz Arms G4 non-reciprocating billet upper receiver. Complete with an ultra-smooth rifle-length gas block system, a 15-inch free-float M-LOK handguard, a pre-headspaced side-charging bolt carrier assembly, and a full matching lower build component package, this kit delivers everything required to seamlessly transform any standard stripped lower receiver into an optimized hunter or precision benchrest asset.

Key Features

Stationary Side-Charging Interface: Replaces standard rear charging pull tabs with an ergonomic left-side manual handle that runs independently from the bolt carrier's cycling path. The handle stays fully static while firing, eliminating structural interference with optics or support hand holds and sealing off the receiver rear against venting diagnostic gases.
All-In-One Complete Rifle Build Package: Takes the technical guesswork out of specialized assembly. This matching master configuration ships complete with a pre-headspaced side-charging BCG, lower parts kit, polished fire control trigger assembly, and standard adjustable stock setup to finish a stripped lower receiver out of the box.
Versatile 1:8 Twist Rate: Precision button-rifled with an optimized 1:8 twist configuration engineered specifically to maximize rotational velocity and stability across a wide span of projectile profiles, ensuring sub-MOA precision on lightweight target rounds up to heavy 123gr and 130gr hunting bullets.
Maximized 20-Inch Bore Combustion: The extended 20-inch barrel allows slow-burning precision rifle powders to reach full expansion and optimal velocity metrics, ensuring rounds remain supersonic past extended distance boundaries.
Melonite/Nitride Barrel Protection: The heavy-duty 4150 CMV steel barrel is fully treated with an advanced Salt Bath Melonite finish inside and out. This premium chemical hardening vastly extends bore life against rapid gas erosion at the port and shields against moisture.
Ultra-Smooth Rifle-Length Gas Dwell: Pairing a precision 20-inch barrel with a true rifle-length gas tube drops internal carrier pressure, establishing an exceptionally soft recoil impulse that limits benchrest scope disruption.
Slim Profile Free-Float M-LOK Rail: Crafted from premium 6061-T6 aluminum, the free-float rail isolates barrel vibrations to preserve uniform mechanical accuracy while providing massive M-LOK modular real estate.

Technical Specifications

Upper Receiver	Gibbz Arms G4 Non Reciprocating Side Charging Billet Aluminum Receiver with Gen 2 Handle, M4 Feed Ramps, Type III Hardcoat Anodized Black
Charging Style	Left-Side Non-Reciprocating Manual Cocking Handle Assembly (Stays Stationary While Firing)
Bolt Carrier Group	Premium Milspec BCG, Nitride/Melonite Finish, M16 Carrier, Properly Staked Gas Key, MPI Tested, Equipped with Correct 6.5 Grendel Type II Bolt face
Barrel Length & Steel	20 Inch Profile, 4150 Chrome Moly Vanadium Steel, Medium Contour, Melonite Treated
Caliber	6.5 Grendel (Type II Face Depth of .136")
Twist Rate	1:8 Twist (Optimized to stabilize standard range, match, and hunting bullet profiles)
Gas Operating Block	Rifle-Length System, Low-Profile Gas Block Machined from 4140 Steel, Stainless Steel Gas Tube
Muzzle Device	Standard 5/8x24 Thread Pitch, A2 Birdcage Flash Hider with Crush Washer Pre-Installed
Handguard	15 Inch Slim Profile Free-Float M-LOK Rail, Full-Length Top Picatinny Rail, Machined from 6061-T6 Aluminum
Lower Parts Kit	Mil-Spec Polished Trigger & Hammer, Standard Pistol Grip, Lower Component Springs, and Pins Included
Stock Assembly	Standard Mil-Spec M4 Stock with 6-position buffer tube, standard 3oz buffer, buffer spring, latch plate, and castle nut
Manufacturing Origin	100% Made in the USA with Pro2A Tactical Lifetime Factory Warranty

Why Choose This Product?

The PRO2A 20" 6.5 Grendel NR Side Charging Melonite Upper Kit directly solves the three biggest hurdles facing precision medium-to-long range builders: optimizing gas system geometry for low-recoil control, uncomfortable manual manipulations beneath large scopes, and part-by-part home building tolerances. While short-gassed setups can exhibit jagged, violent operations when stepping up to a 6.5 Grendel cartridge, Pro2A Tactical marries an extended 20-inch barrel path to a true rifle-length gas network. This arrangement balances internal carrier velocities, generating an incredibly soft impulse that lets you track impacts through your optic continuously without losing your frame.

Moving your manual charging interface to a static side layout fundamentally accelerates your manipulation speeds. You can comfortably charge the chamber or cycle clearing paths from a natural firing position without disrupting your optical line of sight, breaking your cheek weld over the stock, or reaching over the top of massive target turrets. Furthermore, by investing in a comprehensive, complete build kit rather than piecing your components together block-by-block, you eliminate dangerous headspace variations and tracking issues between distinct manufacturers. Backed completely by Pro2A Tactical's signature Lifetime Factory Warranty and engineered with 100% American craftsmanship, this master kit converts your stripped lower receiver into a premium, duty-ready long-range asset with absolute confidence.