*CONTACT US FOR A SPECIAL COUPON CODE!*
Primary Weapons Systems MK111 Mod 2-M .223 Wylde 11.85" Complete Upper Receiver Assembly - MK1-M2U-223-11
Product Description
Deploying a short-barreled rifle (SBR) or AR pistol configuration for close-quarters duty, vehicular operation, or suppressed tactical lanes reveals an immediate mechanical and environmental bottleneck: harsh direct gas impingement (DI). Shortening a direct impingement gas path down to 11 inches results in violently increased cyclic rates, over-gassed receiver blowback, and rapid carbon slurry accumulation. This severe fouling bakes onto your bolt assembly under high thermal pressure, degrading reliability and introducing a barrage of premature extraction errors. The **Primary Weapons Systems (PWS) MK1 Mod 2-M 11.85" Upper Receiver Assembly** completely eliminates these operational limits, dropping a world-class, multi-step **long-stroke piston system** onto your lower receiver to ensure clean, ultra-smooth operation in the most demanding conditions.
Precision-engineered in Boise, Idaho, from a custom-forged 7075-T6 structural aluminum block, the MK111 Mod 2-M unibody chassis maximizes stiffness while drastically dropping front-end mass. By eliminating traditional forward assist structures, PWS trims away unnecessary thickness, creating a sleek, snag-free silhouette. The entire receiver shell and matching handguard are wrapped in a rich, uniform MIL-SPEC Type III hardcoat anodized black jacket that actively repels trail moisture, chemical bore solvents, and abrasive field friction. At its heart is a match-grade 11.85-inch Chrome-Moly Vanadium steel barrel chambered in **.223 Wylde**. This custom barrel configuration utilizes a tight, optimized chamber geometry that safely stabilizes both high-pressure 5.56x45mm NATO duty cartridges and commercial .223 Remington target loads with equal, sub-MOA precision.
The true operational crown jewel of the MK1-M2U-223-11 model is its elite long-stroke piston operating engine. Unlike traditional DI systems that vent dirty carbon blast directly back into the receiver tracks, the PWS design links the bolt carrier group to a full-length steel operating rod and gas piston head. Expanding gas pushes the piston rod backward to cycle the action, venting carbon safely out of the forward gas block ports and leaving the receiver internals clean, cool, and dry. Outfitted with an **adjustable 3-position gas regulator block**, operators can instantly dial in gas restriction levels to balance cyclic velocity when transitioning between unsuppressed drills and heavy suppressor work. Featuring the proprietary 11-inch PWS PicMod™ handguard—which blends standard Picatinny rail blocks with open M-LOK layout windows—this premium upper receiver brings unparalleled suppressed dominance directly to your tactical build.
*Armorer Bench Notes & Technical Maintenance Guidance: The Primary Weapons Systems MK111 Mod 2-M upper assembly ships 100% complete from the factory, pre-fit with a specialized long-stroke piston bolt carrier group and a premium Radian Raptor-LT™ ambidextrous charging handle. It drops natively onto any mil-spec AR-15 lower receiver assembly using standard 0.250" pivot and takedown pins. Suppressed Operating Instructions: The integrated 3-position gas block is adjustable through the forward handguard window utilizing the included PWS gas tool or a standard flathead driver: Position 1 is calibrated for standard unsuppressed firing; Position 2 is optimized for high-velocity suppressed loads; Position 3 is dialed for low-pressure/heavy-suppressor duty strings. Because carbon is isolated to the forward gas cylinder, routine post-range cleaning on your bench is incredibly fast—simply wipe the dry BCG with a microfiber cloth. Periodically remove the forward gas plug to brush out baked-on carbon scale from the gas cylinder using a nylon bore brush and a light solvent to ensure the adjustment valve continues to click true.
Key Features
- Long-Stroke Piston Operating System: Combines the cycling smoothness of an AK with the accuracy of an AR, cycling carbon completely away from the receiver to let your bolt run cool and clean.
- Adjustable 3-Position Gas Block: Provides immediate manual gas adjustments to flatten out recoil impulse, slow down carrier velocity, and eliminate toxic gas blowback when shooting suppressed.
- Match-Grade .223 Wylde Chambering: 11.85" CMV barrel features a hybrid .223 Wylde chamber and 1:8 twist rate, optimizing downrange ballistic accuracy across both 5.56 NATO and .223 Rem payloads.
- Proprietary PicMod Handguard: Features an elite free-float handguard that mounts standard Picatinny accessories at the muzzle tip while providing lightweight M-LOK slots along the sides.
- Premium Hardware Enhancements: Arrives factory-loaded with a specialized PWS long-stroke carrier group, Radian Raptor-LT ambi charging handle, and a PWS FRC muzzle compensator.
Product Specifications
- Brand: Primary Weapons Systems (PWS)
- Model Line: MK1 Mod 2-M Complete Upper Receiver Groups (MK111 Platform)
- MPN/SKU: MK1-M2U-223-11 (Also tracked as 1M111UA0B)
- UPC Code Profile: 811154033208
- Caliber Focus: .223 Wylde (Safely Feeds Both 5.56x45mm NATO & .223 Remington)
- Barrel Length Specification: 11.85 Inches (301mm Short-Barreled Rifle / Pistol Profile)
- Operating System Type: Adjustable Long-Stroke Piston Drive (Direct Impingement Alternative)
- Gas Block Architecture: 3-Position Adjustable Gas Regulator Block (Forward Facing)
- Barrel Material Lineage: 4150 Chrome-Moly Vanadium Steel (Button Rifled / Nitride Coated)
- Barrel Twist Orientation: 1:8 Inch Right-Hand Twist Rate
- Upper Receiver Style: Custom-Forged 7075-T6 Structural Aluminum (No Forward Assist Profile)
- Handguard System: 11.0" Free-Float PicMod™ Modular M-LOK & Picatinny Rail
- Exterior Finish Shield: Type III Class 2 Hardcoat Matte Black Anodization
- Bolt Carrier Group: Included Specialized PWS Long-Stroke Piston BCG (Salt Bath Nitride Finish)
- Charging Handle Interface: Included Radian Raptor-LT Ambidextrous Charging Handle
- Muzzle Device Interface: PWS FRC (F槍 Muzzle Compensator) Pre-Installed (1/2x28 Thread Pitch)
- Net System Weight: 4.41 lbs (4 lbs 6.5 oz Assembled Weight)
- Country of Manufacture: United States of America (Boise, Idaho)
