
Availability: In Stock
Current Stock: Out of stock
The Primary Weapons Systems MK114 MOD 1-M upper receiver in .223 Wylde with a 14.5" barrel brings PWS's proven piston reliability to a compact, versatile platform. Built around the PWS long-stroke piston system with a 3-position adjustable gas regulator, this upper delivers consistent performance whether you're running suppressed, unsuppressed, or somewhere in between. The .223 Wylde chamber accepts both 5.56 NATO and .223 Remington ammunition, giving you flexibility at the range or in the field without compromise.
The upper itself is forged from 7075-T651 aluminum and finished with hard coat anodize per Mil-8625 Type III Class 2—that's the same durability spec you'll find on military-grade builds. The 14.5" barrel twist rate of 1:8 stabilizes everything from light 55-grain loads to heavier match rounds. The integrated M-Lok handguard measures 13.624" and provides ample real estate for mounting optics, lights, or other accessories without unnecessary bulk. A Radian Raptor ambidextrous charging handle rounds out the package, ensuring smooth operation regardless of your dominant hand or shooting position.
This is a complete upper receiver assembly—no lower required to run it. Note that no muzzle device is included, giving you the freedom to choose your own brake, flash hider, or suppressor setup. All NFA regulations apply to any muzzle devices you select. Whether you're building a carbine for 3-gun, home defense, or general purpose shooting, the MK114 MOD 1-M delivers the gas system refinement PWS is known for in a no-nonsense, mid-length platform.
| Caliber | .223 Wylde |
| Barrel Length | 14.5" |
| Barrel Twist Rate | 1:8 |
| Barrel Material | 41V50 Steel |
| Operating System | PWS Long-Stroke Piston |
| Gas System Length | Mid-Length |
| Gas Regulator | 3-Position Adjustable |
| Muzzle Velocity | 2,921 fps |
| Upper Receiver Material | 7075-T651 Aluminum, Hard Coat Anodize (Mil-8625 Type III Class 2) |
| Handguard | PWS M-Lok, 13.624" Length, 1.7" Width, 2.25" Height |
| Charging Handle | Radian Raptor Ambidextrous |
| Muzzle Device | Not Included |
The .223 Wylde chamber is designed to safely fire both 5.56 NATO and .223 Remington ammunition. This gives you maximum flexibility when selecting rounds for the range or field use.
Yes. The MK114 MOD 1-M is a complete upper assembly that pairs with any standard AR-pattern lower receiver using the standard takedown pins.
No. The upper is shipped without a muzzle device, allowing you to choose your own brake, flash hider, or suppressor to match your intended use. All NFA regulations apply to any devices you select.
Yes. The integrated 3-position adjustable gas regulator lets you tune the system to your specific ammunition, suppressor setup, or shooting conditions for optimized reliability and reduced felt recoil.

SKU: 121688673 • Weight: 5.14oz





Availability: In Stock
Current Stock: Out of stock
The Primary Weapons Systems MK114 MOD 1-M upper receiver in .223 Wylde with a 14.5" barrel brings PWS's proven piston reliability to a compact, versatile platform. Built around the PWS long-stroke piston system with a 3-position adjustable gas regulator, this upper delivers consistent performance whether you're running suppressed, unsuppressed, or somewhere in between. The .223 Wylde chamber accepts both 5.56 NATO and .223 Remington ammunition, giving you flexibility at the range or in the field without compromise.
The upper itself is forged from 7075-T651 aluminum and finished with hard coat anodize per Mil-8625 Type III Class 2—that's the same durability spec you'll find on military-grade builds. The 14.5" barrel twist rate of 1:8 stabilizes everything from light 55-grain loads to heavier match rounds. The integrated M-Lok handguard measures 13.624" and provides ample real estate for mounting optics, lights, or other accessories without unnecessary bulk. A Radian Raptor ambidextrous charging handle rounds out the package, ensuring smooth operation regardless of your dominant hand or shooting position.
This is a complete upper receiver assembly—no lower required to run it. Note that no muzzle device is included, giving you the freedom to choose your own brake, flash hider, or suppressor setup. All NFA regulations apply to any muzzle devices you select. Whether you're building a carbine for 3-gun, home defense, or general purpose shooting, the MK114 MOD 1-M delivers the gas system refinement PWS is known for in a no-nonsense, mid-length platform.
| Caliber | .223 Wylde |
| Barrel Length | 14.5" |
| Barrel Twist Rate | 1:8 |
| Barrel Material | 41V50 Steel |
| Operating System | PWS Long-Stroke Piston |
| Gas System Length | Mid-Length |
| Gas Regulator | 3-Position Adjustable |
| Muzzle Velocity | 2,921 fps |
| Upper Receiver Material | 7075-T651 Aluminum, Hard Coat Anodize (Mil-8625 Type III Class 2) |
| Handguard | PWS M-Lok, 13.624" Length, 1.7" Width, 2.25" Height |
| Charging Handle | Radian Raptor Ambidextrous |
| Muzzle Device | Not Included |
The .223 Wylde chamber is designed to safely fire both 5.56 NATO and .223 Remington ammunition. This gives you maximum flexibility when selecting rounds for the range or field use.
Yes. The MK114 MOD 1-M is a complete upper assembly that pairs with any standard AR-pattern lower receiver using the standard takedown pins.
No. The upper is shipped without a muzzle device, allowing you to choose your own brake, flash hider, or suppressor to match your intended use. All NFA regulations apply to any devices you select.
Yes. The integrated 3-position adjustable gas regulator lets you tune the system to your specific ammunition, suppressor setup, or shooting conditions for optimized reliability and reduced felt recoil.
SKU: 121688673 • Weight: 5.14oz
