PRO2A 5.5" 40 S&W 1/16 Pistol Caliber Melonite M-LOK Upper Kit with Flash Can

Build the ultimate ultra-compact, heavy-duty defensive pistol with the PRO2A 5.5" 40 S&W Pistol Caliber Melonite M-LOK Upper Kit with Flash Can. This 100% American-made master build bundle contains every critical component required to transform a standard stripped pistol lower receiver into a finished tactical asset. Built around an ultra-compact 5.5-inch 4150 CMV steel barrel, this kit features an integrated blast-forward flash can tucked cleanly inside a modular free-float M-LOK rail to project firing concussions safely downrange. Complete with a ramped blowback bolt carrier group, a full lower parts kit (LPK), and a matching pistol buffer extension with a stabilizing blade assembly, this package bypasses individual hardware tuning to ensure smooth out-of-the-box performance.

Key Features

All-In-One Complete Pistol Package: Eliminates technical tracking hurdles by bundling the side-charging upper, tucked linear flash director, ramped 40 S&W blowback bolt group, full lower internal hardware, and matching pistol blade setup together.
Blast-Forward Linear Flash Can: Pre-installed muzzle device redirects intense short-barrel gas expansions, sound waves, and concussive reports directly downrange—maximizing comfort during fast-paced close-quarters operation.
Advanced Melonite Barrel Protection: Premium 4150 CMV steel barrel is fully treated with an advanced Salt Bath Melonite finish inside the bore and across the exterior to extend service life and offer total protection against moisture and wear.
Ramped Direct Blowback BCG: Gas-less operation utilizing a high-durability blowback bolt group tailored to feed flawlessly from standard pistol caliber lower configurations and compatible Glock profile magazines.
Pistol Blade & LPK Hardware Included: Complemented by a high-strength stabilizing blade extension and a complete, unified lower parts layout to wrap up your entire defensive build smoothly.

Technical Specifications

Upper Receiver Assembly	Mil-Spec Billet Aluminum, Dedicated Slick-Side Pistol Caliber Layout (No Forward Assist/Dust Cover), PCC Sized Ejection Port, Type III Hardcoat Anodized Black Finish
Bolt Carrier Group (BCG)	Premium Direct Blowback Ramped BCG, High-Strength Steel Bolt Face, Nitride/Melonite Finish, Glock Magazine Compatible
Charging Handle	Standard Mil-Spec Aluminum Charging Handle Assembly
Barrel Component	5.5 Inch Profile, 4150 Chrome Moly Vanadium (CMV) Premium Steel, Melonite Treated Interior & Exterior Bore
Caliber	.40 S&W (Pistol Caliber)
Twist Rate	1:16 Twist
Operating System	Direct Blowback (Gas-less operation, no gas block or tube configuration required)
Muzzle Device Component	Standard 9/16x24 Thread Pitch, Slimline Blast-Forward Linear Flash Can Pre-Installed
Handguard Rail	7 Inch Slim Profile Free-Float Aluminum Handguard, Competition Top Picatinny Alignment, Modular M-LOK Attachment Points (Muzzle Device Tucked)
Lower Receiver Parts Kit (LPK)	Complete AR-15 Mil-Spec Lower Parts Kit, Includes Springs, Detents, Pins, Single-Stage Hammer/Trigger Assembly, and Standard A2 Pistol Grip
Pistol Blade Assembly	Pistol Stabilizing Blade, Heavy-Duty Slick AR-15 Pistol Buffer Tube, Specialized Heavy 8oz PCC 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?

Piecing together an ultra-short .40 S&W pistol build manually can lead to frustrating cycling failures, weak extraction, and harsh concussion due to incorrect buffer weights and gas-less blowback pressures. The PRO2A 5.5" .40 S&W Upper Kit with Flash Can directly solves these issues by packaging a specialized heavy pistol buffer, a pre-headspaced ramped BCG, and an integrated linear blast director into a single, cohesive bundle. By including a stabilizing blade assembly and lower internal hardware, you get a fluid, highly ergonomic defense build that operates reliably out of the box. Hand-assembled and quality-tested in the USA, this complete conversion package maximizes your value while keeping the overall footprint highly packable.