Primary Weapons Systems MK111 Mod 2 Complete Upper Features The Primary Weapons Systems MK111 Mod 2 Upper runs on the company s Long Stroke Piston System a design renowned for its reliability and reduced fouling compared to traditional direct impingement systems. A 3-setting adjustable gas system lets the shooter fine tune gas flow across different ammunition types and environmental conditions which also allows the system to be optimized specifically for suppressor use. Running suppressed with this gas system minimizes back pressure reduces gas blowback into the shooter s face and keeps the overall shooting experience cleaner and more comfortable. The 11.85 inch barrel is precision made in Boise and backed by a sub-MOA accuracy guarantee when fed high grade ammunition a serious claim for a barrel this length. Chambered in .223 Wylde this upper accommodates both .223 Remington and 5.56mm NATO ammunition while being tuned for tighter tolerances and improved accuracy over a standard 5.56 chamber. A PWS FSC 556 muzzle device is designed to mitigate recoil and muzzle rise giving the shooter better control during rapid strings of fire. The innovative PicLok handguard combines Picatinny rail sections with M-LOK slots in one design balancing ergonomics with flexible accessory mounting. A Radian Raptor ambidextrous charging handle ensures smooth reliable operation for both left and right handed shooters rounding out an upper built for serious precision and suppressor performance on the AR-15 platform. Primary Weapons Systems MK111 Mod 2 Complete Upper Specifications Manufacturer: Primary Weapons Systems Model: MK111 Mod 2 Type: Complete Upper Caliber: .223 Wylde Barrel Length: 11.85 Color: Black Finish: Anodized Handguard: PicLok M-LOK Operating System: PWS Long Stroke Piston Gas System: 3-Setting Adjustable Muzzle Device: PWS FSC 556 Charging Handle: Radian Raptor Ambidextrous Compatible Hosts: AR-15 Available At: GrabAGun