Mk109 Mod 1-M Upper Receiver 9.75 Barrel 300Blk

Prices last checked September 2026. Prices and availability change often, so confirm on the retailer's site.

The Primary Weapons Systems MK1 MOD 1-M line of upper receivers feature the PWS long stroke piston system. Internally, this line offers the tried and true system that PWS owners have grown to know and love. Featuring a free-float MLOK handguard, forward assist controls, and a more true to mil-spec design, the MK1 MOD 1-M line is a go-to for not only civilians, but also Law Enforcement. With the fully forged upper, the MK1 MOD 1-M is a no-nonsense tool for when you need a high value option that is relentless and unstoppable.

PWS bring back the original MK109 in 300BLK. The 9.75" barrel length provides excellent reliability with a range of ammunition and still function well, with or without a suppressor and without the need for an adjustable gas system.
The MK109 includes the Triad 30 Compensator.

• Long stroke piston system
• M-LOK handguards
• Includes Radian Raptor Charging Handle
• 1:8 barrel twist rate

With the fully forged upper, the MK1 MOD 1-M is a no-nonsense tool for when you need a high value option that is relentless and unstoppable.
All NFA rules apply.