Discover the PWS MK118 MOD 2 Upper 6mm ARC — a premium long-range precision complete upper receiver engineered for shooters who demand maximum ballistic performance and reliability.
This upper features an 18″ 6mm ARC barrel paired with Primary Weapons Systems’ renowned long-stroke piston operating system. The result is a flat-shooting, low-recoil, highly accurate platform that outperforms traditional .223/5.56 at extended distances while maintaining cleaner operation and superior reliability compared to direct impingement uppers.
The MK118 MOD 2 upper is designed to pair perfectly with MOD 2-M ambidextrous lowers, making it the ideal choice for building a dedicated precision rifle, long-range target gun, or versatile hunting rifle.
Key Features & Benefits
- Long-Stroke Piston System: Exceptional reliability with minimal carbon fouling and gas blowback. Features a 3-position adjustable gas regulator for perfect tuning with or without a suppressor.
- 18″ 6mm ARC Barrel: Precision barrel with 1:7.5 twist rate, optimized for the high-performance 6mm ARC cartridge. Delivers outstanding velocity, flat trajectory, and sub-MOA accuracy at long range.
- MOD 2 Forged Upper: Lightweight forged 7075-T6 aluminum receiver with modern styling and enhanced ergonomics.
- 15″+ Extended M-LOK Handguard: Slim, free-floating design offers maximum accessory mounting space for bipods, optics, and other precision accessories.
- Suppressor Optimized: Low back-pressure piston system excels with modern suppressors for quiet, precision shooting.
- Premium Components: Enhanced PWS bolt carrier group, precision-matched internals, and high-quality muzzle device compatibility.
- Superior Ballistics: 6mm ARC offers significantly better long-range performance and wind resistance than 5.56 NATO.
Why Choose the PWS MK118 MOD 2 6mm ARC Upper?
The combination of the efficient 6mm ARC cartridge and PWS’s proven long-stroke piston system creates one of the best precision piston uppers available. It provides softer recoil, easier maintenance, and greater reliability than standard gas-impingement platforms. Manufactured in the USA, this upper is perfect for competitive long-range shooting, precision hunting, and tactical applications where accuracy at distance matters most.
Technical Specifications
- Caliber: 6mm ARC
- Barrel Length: 18″ with 1:7.5 Twist
- Gas System: Mid-Length Long-Stroke Piston with 3-Position Adjustable Regulator
- Handguard: Extended Free-Float M-LOK
- Upper Receiver: Forged 7075-T6 MK118 MOD 2
- Operating System: PWS Long-Stroke Piston
- Finish: Hardcoat Anodized Black
- Compatibility: Designed for MK1 MOD 2 / MOD 2-M ambidextrous lowers
Take your long-range game to the next level. Add the PWS MK118 MOD 2 Upper 6mm ARC 18″ to your cart today for unmatched precision and piston-driven reliability.
















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