+1-800-504-5897 Help Center Check Order Status
About Us Policies Reviews How To
Free Shipping & Free Returns*

FREE SHIPPING on Over 250,000 Products

Shop now and get Free Value Shipping on most orders over $49 to the contiguous 48 states, DC, and to all U.S. Military APO/FPO/DPO addresses.

Enjoy our FREE RETURNS

We want to ensure that making a return is as easy and hassle-free as possible! If for any reason you are not satisfied with your purchase, simply return the item within 30 days of receipt, and we'll cover the cost of return shipping. Learn more about our Return Policy.

  • Entire Store
  • ...
  • Apparel & Footwear
  • Astronomy
  • Everything Else
  • Eyewear
  • Hunting Gear
  • Lab Equipment
  • Military Gear
  • Outdoor Gear
  • Photography Equipment
  • Police, EMS & Fire
  • Shooting
  • Sport Optics
  • Sports & Hobbies
TIP
Shopping Cart

Primary Weapons Systems MK1 MOD 1-P Upper Receiver MK1-M1U-223-14-PW Caliber: .223 Wylde, Overall Length: 23 in, $80.00 Off w/ Free S&H

Primary Weapon Systems M114UA01-1F MK116 223 Wylde 16 Inch 4140
Primary Weapon Systems M114UA01-1F MK116 223 Wylde 16 Inch 4140
1 of 1 images
Primary Weapon Systems M114UA01-1F MK116 223 Wylde 16 Inch 4140

Tap Tap to Zoom

Government Restriction Government Restriction
Questions & Answers
Can the 11.85 inch barrel MKI Mod 1 Patrol Fire .556? Expert Answer

Any of the .223 Wylde models will be able to fire .223 Remington or 5.56 NATO.

by Nick B., Gear Expert, November 12, 2021
Where is the gas block for the piston system located? The picture looks like the Gas Block piston system is a rifle length 12" system.

Hence it's description as a "long stroke" piston system. The best way to describe it is to describe what you see when you remove the BCG. It is attached to a long rod which ends with a removable piston that sits inside the exhaust chamber. Short stroke systems normally just cause push a rod which sits inside the receiver, to knock rather than blow the bolt back. These PWS systems are, in most opinions, far superior for many reasons. You'll need to look up that info. You won't go wrong with PWS.

by Grant, Verified Owner, September 5, 2020
View All Q&A You Have a Question? Ask!
Customer Reviews
Helpful Positive Review
Fantastic Quality by Ryan W, December 17, 2018
I just got the upper a week or so ago and so far it has been 100%. I do not have a high round count through it since I just got it, but it is a very smooth cycling upper and it fits with no wiggle on my Spikes lower. I believe these P models are supp...
Read More...
1/1 found this helpful
Most Recent Reviews
PWS. PWS PWS PWS by Mr. X, Verified Owner, December 8, 2023
Great product. I have several. If you want something special with great quality And reliability look no further. PWS is my PWS. you will appreciate it if you get one.
Most Recent Reviews
PWS ARs are the best by JT, Verified Owner, September 14, 2017
This is my 5th PWS upper and I absolutely love it. They are the best AR's for the money hands down. Love the piston system for suppressing and all have been extremely accurate. I pair them with the mod 2 lower and they are fairly light as well. I've ...
Read More...
Read All 3 Reviews
Caliber:
.223 Wylde
Overall Length:
23 in
Barrel Length:
14.5 in
Muzzle Device:
FSC 556
Finish:
Anodized Black
Color:
Black
Condition:
New
Additional Features:
12.75 in KeyMod Rail
Included Accessories:
Adjustment Tool, Literature
Weight:
4.1875 lb

Code: 2D5-UFH-MK1MOD1-MK1-M1U-223-14-PW

MPN: MK1-M1U-223-14-PW

UPC: 811154033475

List: $1,209.95Save $80.00
$1,129.95

ATTENTION! We currently do not ship this product to AK, CA, HI, IL, NY, WA, P.O. Boxes, and U.S. Territories. Please see our policies for more information.

Product Info for Primary Weapons Systems MK1 MOD 1-P Upper Receiver

Get the most out of 5.56mm NATO and .223 Remington with the Primary Weapons Systems MK114 MOD 1-M UPPER .223 WYLDE Upper Receiver! These AR15 Upper Receivers will give you the AR15 build you've been dreaming of. This complete upper includes all kinds of proprietary extras like the PWS Long Stroke Piston System and PWS Piston Upper. The PWS M-Lok handguard allows you to add any lights or attachments your heart desires. Now's the time, go Wylde!image

Available with or without a compensator.

Specifications for Primary Weapons Systems MK1 MOD 1-P Upper Receiver:

Product Color: Black

Features of Primary Weapons Systems MK1 MOD 1 Upper Receiver:

  • ADJUSTABLE GAS BLOCK
  • SMOOTH RECOIL IMPULSE
  • THE PWS LONG STROKE PISTON

Package Contents:

  • Primary Weapons Systems MK1 MOD 1-P Upper Receiver

Primary Weapons Systems MK1 MOD 1-P Upper Receiver Orderable Models

List of Orderable Models

  • Primary Weapon Systems MK116 223 Wylde 16 Inch 4140 Steel Chrome-Lined Black Hard Coat Anodized Barrel Finish, MK1-M1U-223-14-PW , MPN: MK1-M1U-223-14-PW , UPC: 811154033475 , Code: 2D5-UFH-MK1MOD1-MK1-M1U-223-14-PW

Primary Weapons Systems MK1 MOD 1-P Upper Receiver Unavailable & Discontinued Models

List of Unorderable Models

  • Primary Weapons Systems MK1, MOD 1 - P Upper Receiver, 16.1 in Barrel, 12.75 in KeyMod Rail, FSC 556, Black, .223 Wylde, M116UA0B , MPN: M116UA0B , Code: 2D5-UFH-MK1MOD1-M116UA0B
  • Primary Weapons Systems MK111 MOD 1 - P Upper Receiver, 11.85 in Barrel, 10 in KeyMod Rail, Triad 556, Black, .223 Wylde, M111UA0B , MPN: M111UA0B , Code: 2D5-UFH-MK1MOD1-M111UA0B
  • Primary Weapons Systems MK107 MOD 1 - P Upper Receiver, 7.75 in Barrel, 7 in KeyMod Rail, Triad 556, Black, .223 Wylde, M107UA0B , MPN: M107UA0B , Code: 2D5-UFH-MK1MOD1-M107UA0B
  • Primary Weapons Systems MK116 MOD 1 - P Upper Receiver, 16.1 in Barrel, 12.75 in KeyMod Rail, FSC 30, Black, .300BLK, M116UB0B , MPN: M116UB0B , Code: 2D5-UFH-MK1MOD1-M116UB0B
  • Primary Weapons Systems MK111 MOD 1 - P Upper Receiver, 11.85 in Barrel, 10 in KeyMod Rail, Triad 30, Black, .300BLK, M111UB0B , MPN: M111UB0B , Code: 2D5-UFH-MK1MOD1-M111UB0B
Compare (0)
1 item has been added
Add at least two items to compare