Availability: In Stock
Current Stock: Out of stock
The Primary Weapons Systems Mk118 Mod 2-M upper receiver in 6 ARC delivers precision and reliability for long-range shooters and competitive marksmen who demand a complete, ready-to-run upper assembly. Built on PWS's proven Mk118 platform, this 6 ARC upper pairs a dedicated 18-inch barrel with a proven gas system optimized for accuracy and consistent performance downrange. The threaded muzzle gives you the freedom to add your choice of suppressors or muzzle devices, while the cold-hammer-forged barrel ensures durability through thousands of rounds.
6 ARC has earned a solid reputation in precision rifle circles as a flat-shooting, efficient cartridge that delivers excellent energy retention at distance while remaining controllable in rapid-fire sequences. The 18-inch barrel length strikes a practical balance between velocity and maneuverability—long enough to wring out the round's inherent accuracy, short enough for practical handling in real-world conditions. PWS barrels are known for tight bore tolerances and consistent performance, which matters when you're zeroing in on distant targets.
This is a complete upper receiver assembly, so it's ready to integrate with your existing lower receiver and furniture. Whether you're building a dedicated long-range platform, a precision service rifle, or upgrading an existing AR-pattern rifle, the Mk118 Mod 2-M upper brings proven PWS engineering and the efficiency of 6 ARC to your setup. The threaded muzzle accepts standard 5/8-24 devices, giving you the flexibility to tailor the rifle to your mission.
| Manufacturer | Primary Weapons Systems |
| Model | Mk118 Mod 2-M |
| Caliber | 6 ARC |
| Barrel Length | 18 inches |
| Muzzle Thread | 5/8-24 (threaded) |
| Type | Complete upper receiver assembly |
This is a standard AR-15 pattern upper receiver assembly and will mate with any AR-15 compatible lower receiver. You'll need to provide your own lower and fire control components to complete the rifle.
6 ARC is engineered for precision shooting at distance, offering excellent ballistic coefficients, minimal wind drift, and reliable energy retention beyond 500 yards. It's also more ammunition-efficient than larger magnum rounds and remains controllable in rapid-fire or tactical sequences.
Yes. The muzzle is threaded 5/8-24, which is the standard commercial suppressor thread pitch. You can attach any suppressor with this thread specification.
This is a complete upper receiver assembly only. You'll need to source a separate lower receiver, stock, grip, trigger, and charging handle to complete a functional rifle.

SKU: 152742936 • Weight: 5.65oz




Availability: In Stock
Current Stock: Out of stock
The Primary Weapons Systems Mk118 Mod 2-M upper receiver in 6 ARC delivers precision and reliability for long-range shooters and competitive marksmen who demand a complete, ready-to-run upper assembly. Built on PWS's proven Mk118 platform, this 6 ARC upper pairs a dedicated 18-inch barrel with a proven gas system optimized for accuracy and consistent performance downrange. The threaded muzzle gives you the freedom to add your choice of suppressors or muzzle devices, while the cold-hammer-forged barrel ensures durability through thousands of rounds.
6 ARC has earned a solid reputation in precision rifle circles as a flat-shooting, efficient cartridge that delivers excellent energy retention at distance while remaining controllable in rapid-fire sequences. The 18-inch barrel length strikes a practical balance between velocity and maneuverability—long enough to wring out the round's inherent accuracy, short enough for practical handling in real-world conditions. PWS barrels are known for tight bore tolerances and consistent performance, which matters when you're zeroing in on distant targets.
This is a complete upper receiver assembly, so it's ready to integrate with your existing lower receiver and furniture. Whether you're building a dedicated long-range platform, a precision service rifle, or upgrading an existing AR-pattern rifle, the Mk118 Mod 2-M upper brings proven PWS engineering and the efficiency of 6 ARC to your setup. The threaded muzzle accepts standard 5/8-24 devices, giving you the flexibility to tailor the rifle to your mission.
| Manufacturer | Primary Weapons Systems |
| Model | Mk118 Mod 2-M |
| Caliber | 6 ARC |
| Barrel Length | 18 inches |
| Muzzle Thread | 5/8-24 (threaded) |
| Type | Complete upper receiver assembly |
This is a standard AR-15 pattern upper receiver assembly and will mate with any AR-15 compatible lower receiver. You'll need to provide your own lower and fire control components to complete the rifle.
6 ARC is engineered for precision shooting at distance, offering excellent ballistic coefficients, minimal wind drift, and reliable energy retention beyond 500 yards. It's also more ammunition-efficient than larger magnum rounds and remains controllable in rapid-fire or tactical sequences.
Yes. The muzzle is threaded 5/8-24, which is the standard commercial suppressor thread pitch. You can attach any suppressor with this thread specification.
This is a complete upper receiver assembly only. You'll need to source a separate lower receiver, stock, grip, trigger, and charging handle to complete a functional rifle.
SKU: 152742936 • Weight: 5.65oz
