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A Cost-Effective, Long-Stroke Piston Upper Exclusively From Brownells!

The Primary Weapons System long-stroke gas-piston upper receiver is one of the more-innovative developments to hit the AR-15 market in recent years, and now, you can get your hands on a unique variant of this system straight from Brownells! The PWS MK109 PRO upper receiver chambered in 300 Blackout contains everything you need to get your AR-15 set up right.

Of course, this system features the unique, long-stroke system that Primary Weapons Systems upper receivers are known for, plus this system includes a few extras that make it a must-have! The PWS upper is a complete system, so you'll get a bolt-carrier group, as well as a Radian Weapons Raptor charging handle.

  • Barrel length: 9.75 inches
  • Overall length: 18.5 inches
  • Weight: 3 pounds, 10 ounces
  • All-black finish

Other features found in the PWS MK109 PRO upper receiver include a free-float, M-LOK handguard, an adjustable gas system and a short barrel equipped with an optimized 1:8-inch twist rate.

PRIMARY WEAPONS - MK109 PRO UPPER RECEIVER COMPLETE 300 BLACKOUT

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In Stock

Cartridge: 300 AAC Blackout

Finish: Black

Style: Complete

Length: 18.5"

Muzzle: Flash Hider

Twist: 1-8