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

Extended Long-Range Ballistics and Hunting Dominance in an All-In-One Build Package

Push the intermediate AR-15 platform to its absolute performance limits. The PRO2A 20" 6.5 Grendel Rifle-Length Melonite AR-15 Upper Kit is a comprehensive all-in-one assembly package containing a complete precision upper receiver assembly, a premium Mil-Spec bolt carrier group (BCG) with an optimized Type II bolt face, an aluminum charging handle, a complete lower parts kit, and a 6-position adjustable stock assembly. Engineered around a full 20-inch 4150 CMV steel barrel, this configuration maximizes complete powder burn to unlock the full velocity potential of the 6.5 Grendel cartridge. The true rifle-length gas system smooths system pressure, delivering flat trajectories, minimized wind drift, and exceptional terminal kinetic energy past the 800-yard mark. This complete bundle contains everything needed to cleanly transform your stripped lower receiver into a finished long-range tack-driver. Proudly 100% designed, machined, and precision-tested in the USA.

Key Features

All-In-One Complete Rifle Build Package: Takes the technical guesswork out of component matching. This master kit ships complete with a matching Type II side-charging/rear bolt carrier group, charging handle, polished trigger assembly, lower parts kit, and an adjustable stock setup pre-inspected for exact headspace integration.
Maximized 20-Inch Muzzle Velocity: The full 20-inch barrel allows slow-burning rifle powders to reach peak expansion and velocity metrics, maximizing downrange impact energy for medium game hunting and target work.
Ultra-Smooth Rifle-Length Gas Dwell: Sprints past shorter gas networks by dropping in a true rifle-length gas tube. This configuration tames port pressures and slows bolt carrier speed for a incredibly soft recoil impulse and fast follow-up shots.
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 and protects against harsh outdoor field elements.
Versatile 1:8 Twist Rate Profile: Precision button-rifled with a clean 1:8 twist rate configuration engineered to perfectly stabilize a massive profile array of heavy, high-BC match projectiles up to 130-grain and popular supersonic hunting options cleanly.
Slim Profile Free-Float M-LOK Rail: Built from durable 6061-T6 aluminum, the free-float handguard completely isolates barrel vibrations to preserve uniform mechanical accuracy while offering extensive modular M-LOK attachment surfaces.

Technical Specifications

Upper Receiver	Mil-Spec Forged 7075-T6 Aluminum, M4 Feed Ramps, Type III Hardcoat Anodized Black Finish (Forward Assist & Ejection Port Cover Pre-Installed)
Bolt Carrier Group	Premium M16 Profile Mil-Spec BCG, Nitride/Melonite Finish, Optimized True Type II Bolt Face (.136" Face Depth), Properly Staked Gas Key
Charging Handle	Standard Mil-Spec Aluminum Charging Handle
Barrel Length & Steel	20 Inch Profile, 4150 Chrome Moly Vanadium Steel, Heavy/Medium Contour, Melonite Treated
Caliber	6.5 Grendel (Type II)
Twist Rate	1:8 Twist (Optimized to stabilize standard, match grade, and supersonic hunting projectiles)
Gas Operating Block	Rifle-Length System, Low-Profile Gas Block Machined from 4140 Steel, Stainless Steel Gas Tube
Muzzle Device	Standard 5/8-24 Thread Pitch, A2 Flash Hider with Crush Washer Pre-Installed
Handguard	15 Inch Slim Profile Free-Float M-LOK Rail, Competition 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	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 Rifle Length Upper Kit solves the largest challenge encountered when stepping into long-range intermediate calibers: custom assembly compatibility and component friction. While short barrels are nimble, the 6.5 Grendel cartridge demands full barrel length to unleash its true ballistic potential—matching the supersonic performance of heavy bolt-action rounds from a standard, lightweight semi-automatic platform. By engineering this 20-inch barrel around a true rifle-length gas line, Pro2A Tactical tames system pressure spikes and provides exceptionally soft cycling behavior.