Pro2A 5.5" 10mm Pistol Caliber Melonite M-LOK AR-10mm Upper Receiver

PRO2A 5.5" 10mm 1/16 Pistol Caliber Melonite M-LOK Upper

Description

The Pro2A Tactical 5.5-inch 10mm Auto Pistol Caliber Complete Upper Receiver assembly packs heavy-hitting, full-power performance into an ultra-compact footprint. Carefully hand-assembled and quality verified in Georgia, this upper receiver operates on a rugged and hyper-reliable blowback system specifically optimized for the high pressures of the 10mm cartridge. Featuring a highly maneuverable 5.5-inch barrel with a premium Melonite treatment and a rigid free-float M-LOK rail layout, it serves as an excellent drop-in option for dedicated AR-10mm pistol lower configurations or registered short-barreled rifle lower receivers.

Key Features

Ultra-Compact Hard-Hitter: Packs the formidable kinetic energy of the 10mm Auto cartridge into a tight 5.5-inch barrel profile ideal for close-quarters use, vehicle deployment, and backpacking defense.
Reliable Straight Blowback Action: Built without gas blocks or complex gas tube routing, eliminating standard mechanical failure points to ensure robust cycling with heavy hard-cast and defense loads.
1/16 Standard Twist: Precision-stabilizes standard 180gr and heavy 200gr+ 10mm bullets comfortably for reliable downrange groupings.
Slim M-LOK Modular Rail: Employs a lightweight free-float handguard for easy integration of hand stops, flashlights, or tactical accessories.

Technical Specifications

Upper Receiver	Milspec Billet Aluminum M4 Flat Top Receiver, Ejection Port Optimized for Pistol Calibers, Enhanced Feed Cone (Type III Hardcoat Anodized)
Barrel Length & Profile	5.5-Inch Medium Profile
Caliber	10mm Auto
Twist Rate	1:16 Twist
Barrel Material	4150 Chrome Moly Vanadium Steel with Premium Corrosion-Resistant Melonite Finish
Gas System Length	Not Needed - Straight Blowback Operation
Handguard	4 Inch Free Float Slim Profile M-LOK Rail System with Integrated Top Picatinny Rail
Muzzle Thread & Device	9/16x24 Thread Pitch with Standard A2 Flash Hider

Why Choose This Product?

Transitioning into a hard-hitting 10mm pistol platform requires precise chamber styling and extraction geometric design due to the increased pressures of straight blowback cycling. The Pro2A 5.5" 10mm Upper Receiver addresses this challenge entirely by utilizing an optimized feed ramp contour matched alongside premium 4150 steel manufacturing tolerances. The resilient Melonite surface treatment guarantees maximum bore life, exceptional surface hardness, and worry-free cleanings after using dirty training ammunition. Safe, hard-hitting, and built to withstand rigorous use, it is the perfect drop-in conversion to bring serious firepower to your compact AR collection.

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