• Privacy Policy

No products in the cart.

Sign-up below for New Product Announcements and Offers
  • Privacy Policy
  • RKM-18-1
  • RKM-18-3

Build a Complete 18″ MARK 12 Barrel AR

0 Reviews
0 out of 5

Build a Complete 18″ MARK 12 Barrel, AR Kit. This kit contains everything you need to build your own AR except the stripped lower receiver.

The Kit Contains:

  • Fully assembled 18″ MARK 12 5.56 mm Upper with 15″ Keymod Palm Handguard™
  • Your choice of either an MBA-1 Buttstock Assembly or MBA-3 Buttstock Assembly (Black)
  • Complete Lower Parts Kit

Add to your build with optional add-on parts such as a Velocity Drop-in trigger, or The Lower Enhanc-AR™ Kit.

Complete description below.

Choose from the options below, then Review Configuration and Add to the cart.

Build a Complete 18″ MARK 12 5.56 mm Barrel, AR Kit. This kit contains everything you need to build your own AR except the stripped lower receiver.

The Kit Contains:

  • Fully assembled 18″ MARK 12 5.56 mmUpper with 15″ Keymod Palm Handguard™
  • Your choice of either an MBA-1 Buttstock Assembly or MBA-3 Buttstock Assembly
  • Complete Lower Parts Kit

Add to your build with optional add-on parts such as a Velocity Drop-in trigger, or The Lower Enhanc-AR™ Kit.

This Kit does not come with the lower receiver. You will have to supply a lower receiver purchased elsewhere. We recommend that you look for a Mil-Spec stripped lower.

Includes:

  • Your choice: MBA-1 Fixed Rifle Buttstock assembly or MBA-3 Adjustable Carbine Buttstock Assembly
  • LRPK-1 Complete .223/5.56 Lower Receiver Parts Kit

18″ Mark 12 5.56 mm Complete Upper Barrel Assembly

Includes:

  • HG-V-15K – Palm Handguard™ – Vented 15″ KeyMod with Barrel Nut
  • BAA3-M12 – 18″ Mark12 5.56 mm Barrel
  • FTT-EA1 – A3 Upper Receiver Assembled
  • BC-A-223 – Fully Assembled Bolt Carrier
  • BL-04 – Standard Gas Tube
  • GB-LP750 – Gas Block .750
  • BL-06-A2 — A2 Flash Hider

Barrel Specs:

  • 18″ Mark 12 5.56 mm Barrel
  • 5.56 mm
  • 4140 Chrome Moly
  • Threaded Barrel — Thread Pitch 1/2 x 28
  • 1-9 RH Barrel Twist
  • 6 Lands and Groves
  • M4 Feed Ramp
  • Button Broached
Application

Carbine, Rifle

Buttstock Type

MBA-1, MBA-3

Available Colors

Black

Slot Style

KeyMod

Caliber

.556 mm

Material

4140 Chrome-Moly

Twist

1-9

Lands and Grooves

6

Threaded

Yes

Thread Pitch

1/2 x 28

Weight lbs

10

For best results we recommend following a break-in procedure. We recommend that you clean the chamber and bore after every round for the first 25 rounds. It should take approximately 200 rounds for optimum barrel accuracy. Please keep in mind that accuracy is dependent upon many factors such as bullet weight, powder load, etc. If you have any question regarding our procedure, please ask or give us a call.
Per ammunition guidelines it is not recommended to shoot 5.56mm in a .223 REM  barrel, which we support for best and safest use of our product.