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Primary Weapons Systems MK114 MOD 2-M, .223 Wylde, 14.5in Upper Receiver Up to $100.00 Off w/ Free Shipping — 2 models

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Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, No Compensator, Black, MK1-M2U-223-14-NC
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, No Compensator, Black, MK1-M2U-223-14-NC
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, No Compensator, Black, MK1-M2U-223-14-NC
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, No Compensator, Black, MK1-M2U-223-14-NC
1 of 9 images
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, No Compensator, Black, MK1-M2U-223-14-NC
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW
2 of 9 images
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, No Compensator, Black, MK1-M2U-223-14-NC
3 of 9 images
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, No Compensator, Black, MK1-M2U-223-14-NC
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, No Compensator, Black, MK1-M2U-223-14-NC
4 of 9 images
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, No Compensator, Black, MK1-M2U-223-14-NC
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW
5 of 9 images
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW
6 of 9 images
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW
7 of 9 images
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW
8 of 9 images
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW
9 of 9 images
Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW

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Questions & Answers
Is the muzzle device pinned and welded on the 14.5" barrel making it a total of 16"+?

The FSC556 is pinned and welded for a legal length of 16 inches

by KIRKN8R, Verified Owner, April 11, 2021
See 1 More Answer
Is the device the FSC556 or FRC? It appears to be the FRC556 3-port. The FSC does not have external threads, an the FRC has threads like in the photo. Manufacturer Answer

Our current mk114 uppers ship with a 3 port FRC muzzle device

by Primary Weapons Systems, Manufacturer, March 11, 2026
View All Q&A You Have a Question? Ask!
Customer Reviews
Helpful Positive Review
New To PWS by nhw, Verified Owner, June 8, 2025
Only negative item is man alive was it covered in oil. It wipes off easily enough though. Ran 200 rounds through it at the range. Flawless performance. Burned off oil under the handguard. Cleaned it and Only used a single sheet of a select-a-size pa...
Read More...
3/3 found this helpful
Most Recent Reviews
Pws 14.5 upper reciever by Terry, Verified Owner, June 11, 2024
Awesome upper. Light and well built optics planet has it out to me within a week.
Read All 2 Reviews
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Product Info for Primary Weapons Systems MK114 MOD 2-M, .223 Wylde, 14.5in Upper Receiver

The MK114 MOD 2-M Upper operates on the highly acclaimed PWS Long Stroke Piston System, renowned for its reliability and reduced fouling. The inclusion of a 3-setting Adjustable Gas System allows users to fine-tune gas flow, ensuring optimal performance in diverse shooting conditions as well as optimizing it for suppressor use. This innovative system not only enhances reliability but also provides adaptability to various ammunition types and environmental factors.image

WARNING: California`s Proposition 65

Specifications for Primary Weapons Systems MK114 MOD 2-M, .223 Wylde, 14.5in Upper Receiver:

Manufacturer: Primary Weapons Systems
Caliber: .223 Wylde
Barrel Length: 14.5 in
Gas System Length: Mid Length
Barrel Twist Rate: 1-8
Firearms Threads Per Inch: 1/2x28
Finish: Matte
Color: Black
Fabric/Material: 416R Stainless Steel
Gas Block Journal Size-Diameter: .750 in
Handguard Length: 14.5 in
Gas System Type: Long-Stroke Piston
Magazine Included: No
Condition: New

Features of Primary Weapons Systems MK114 MOD 2-M, .223 Wylde, 14.5in Upper Receiver:

  • PWS Long Stroke Piston System: Renowned for reliability and reduced fouling, with adjustable gas settings for optimal performance.
  • Suppressor Optimized: Provides enhanced suppressor performance by minimizing back pressure, reducing gas blowback, and optimizing gas flow for a cleaner and more comfortable shooting experience.
  • .223 Wylde Chambering: Meticulously designed for outstanding accuracy and reliability, accommodating both .223 Remington and 5.56mm NATO.
  • Lightweight Design: The MK114 upper weighs just 4.3 lbs, ensuring superior maneuverability without compromising performance.
  • Barrel: 14.5" .223 Wylde barrel with a 1:8 twist rate, delivering exceptional accuracy and versatility when firing both .223 Remington and 5.56mm NATO rounds.
  • Muzzle: Threaded 1/2-28 for compensators, muzzle brakes, suppressors and suppressor mounts (sold seperately on this specific upper - no devices included.)
  • Innovative PicLok Handguard: Combining both Picatinny and MLOK into one for mounting accessories, balancing ergonomics and functionality.
  • Radian Raptor Ambidextrous Charging Handle: Ensures smooth operation for both left and right-handed shooters.

Package Contents:

  • Primary Weapons Systems MK114 MOD 2-M, .223 Wylde, 14.5in Upper Receiver

Primary Weapons Systems MK114 MOD 2-M, .223 Wylde, 14.5in Upper Receiver Orderable Models

List of Orderable Models

  • Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, No Compensator, Black, MK1-M2U-223-14-NC , MPN: MK1-M2U-223-14-NC , UPC: 811154033222 , Code: 2D5-URC-RG28D-MK1-M2U-223-14-NC
  • Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, MK1-M2U-223-14-PW , MPN: MK1-M2U-223-14-PW , UPC: 811154033215 , Code: 2D5-URC-RG28D-MK1-M2U-223-14-PW

Primary Weapons Systems MK114 MOD 2-M, .223 Wylde, 14.5in Upper Receiver Unavailable & Discontinued Models

List of Unorderable Models

  • DEMO, Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, Pinned FSC556 Compensator, Black, 18-2M114UA0B , MPN: 18-2M114UA0B-DEMO , Code: 2D5-URC-RG28D-18-2M114UA0B-DEMO
  • DEMO, Primary Weapons Systems MK114 MOD2-M Upper Receiver, .223 Wylde, 14.5in bbl, No Compensator, Black, 18-2M114UA0BNC , MPN: 18-2M114UA0BNC-DEMO , Code: 2D5-URC-RG28D-18-2M114UA0BNC-DEMO
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