Pws Mk111 Mod 1-M Upper 338Arc 11.85 Ls Frc

The Primary Weapons Systems Mk111 Mod 1-M upper receiver in 338 Arcane delivers the kind of precision and reliability that serious riflers expect from PWS. This complete upper assembly combines PWS's reputation for accuracy and durability with the ballistic advantages of the 338 Arc cartridge—a cartridge gaining traction among hunters and target shooters who want more power than 223/5.56 but less recoil and cost than traditional magnum rounds. The 11.85-inch barrel is purpose-built for accuracy, offering a balance between velocity and handling that works across hunting, precision rifle competition, and intermediate-range shooting disciplines.

PWS uppers are known for tight tolerances and attention to detail. The Mk111 Mod 1-M platform has earned respect on the range and in the field. The 338 Arc cartridge itself is becoming the go-to choice for those who want a capable mid-power option without overbore logistics. Whether you're building a new rifle or swapping uppers, this assembly handles the heavy lifting—it's fully finished and ready to mount on a compatible lower receiver.

The 11.85-inch barrel length keeps the rifle compact and maneuverable while preserving enough dwell time and velocity for 338 Arc loadings to perform as intended. This is a no-frills, purpose-driven upper for shooters who know what they want and aren't interested in marketing speak.

Specifications

Frequently Asked Questions

What lower receiver does this PWS 338 Arc upper fit?

The Mk111 Mod 1-M upper is a standard AR-pattern assembly and will accept any mil-spec or compatible AR-15 lower receiver.

Is 338 Arcane the same as 338 ARC?

Yes—338 Arcane and 338 ARC refer to the same cartridge. Both terms are in use in the shooting community.

What is the barrel profile and gas system?

No details on barrel profile, gas tube length, or gas system type are provided for this upper; contact the manufacturer or retailer for those specifications.