Primary Weapons Systems MK114 Mod 2-M Upper Receiver Features The Primary Weapons Systems MK114 Mod 2-M Upper Receiver uses a long-stroke piston system with a 3-setting adjustable gas block that allows tuning for different ammunition or suppressed use. Its 14.5-inch 1:8 twist barrel and mid-length piston layout support the balance and stability expected from a piston-driven AR upper giving shooters a flexible configuration. These characteristics combine to provide steady operation suited for varied range or practical applications. Its T6 7075 forged anodized upper receiver PWS PicLok 13.574-inch handguard and Radian Raptor ambidextrous charging handle offer high-quality ergonomics and accessory compatibility. The PicLok interface supports both Picatinny and M-LOK attachments adding versatility for optic and accessory setup. Built around PWS's proprietary long-stroke piston architecture the MK114 Mod 2-M provides durable construction in a modernized upper receiver system. Primary Weapons Systems MK114 Mod 2-M Upper Receiver Specifications Manufacturer: Primary Weapons Systems Model: MK114 Mod 2-M Caliber: .223 Wylde Barrel Length: 14.5 Operating System: PWS Long Stroke Piston System with 3-Setting Adjustable Gas System Gas System Length: Mid-Length Barrel Twist Rate: 1:8 Upper Receiver: PWS Proprietary Piston Upper T6 7075 Forged Anodized Handguard: PWS PicLok 13.574 (1.7 width 2.25 height) Charging Handle: Radian Raptor Ambidextrous