Primary Weapons Systems MK111 MOD 1-M Complete AR-15 Upper Receiver - .223 Wylde - 11.85"

The Primary Weapons Systems MK111 MOD 1-M Complete AR-15 Upper Receiver in .223 Wylde runs PWS's long-stroke piston system on a 11.85" barrel, keeping the receiver cleaner and cooler than a direct-impingement design under sustained or suppressed fire.

Features:

• 11.85" barrel, 1:8 twist, sub-MOA accuracy guarantee
• .223 Wylde chamber, accepts .223 Remington and 5.56 NATO
• PWS long-stroke piston operating system, adjustable gas block
• Forged 7075 aluminum upper receiver with forward assist
• Free-float M-LOK handguard
• factory-installed FRC compensator
• Radian Raptor ambidextrous charging handle
• Black anodized finish, made in the USA

The long-stroke piston keeps combustion gases out of the receiver entirely, cutting down on the carbon fouling a direct-impingement gun deposits during sustained or suppressed fire, and the adjustable gas block lets you fine-tune cycling for your ammunition and suppressor setup. PWS backs this Boise-made barrel with a sub-MOA accuracy guarantee using quality ammunition, and the MOD 1-M's forward assist adds a familiar mil-spec touch not found on the ambidextrous MOD 2-M line.

Because this 11.85" barrel measures under 16", this complete upper is intended only for an AR pistol or a legally registered short-barreled rifle — attaching it to a standard rifle lower without the correct configuration violates federal law.

Primary Weapons Systems is a U.S.-based manufacturer known for its long-stroke piston AR-15 and AR-10 platforms, backed by the PWS VOW warranty covering repair or replacement for manufacturing defects, and precision manufactured in Boise, Idaho.