Rifle Build Kit - 5.56 | 16" Complete Upper Receiver | M4 6-Positon Stock Kit | BN LPK

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Product Code: RBK-RTB16C55612RA2-TS-M4-6POS-IBOR
MSRP: $639.85
Sale Price: Sale Price: $399.95
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Rifle Build Kit - 5.56 | 16" Complete Upper Receiver with A2 | M4 6 Position Stock and Buffer Tube Kit | Bare Necessities Lower Parts Kit w/ Aluminum Trigger Guard

This product is manufactured based on parts on hand. It may feature a standard or oversized trigger guard, depending on what we have available at the time.

Complete 16" 5.56 Carbine Upper Receiver | 15" M-LOK | BCG & CH:

This Complete 16 inch M-LOK upper receiver comes with a 15 inch free float handguard and is built with only the best Mil-Spec components. The heart of this upper is comprised of a 4150 M4 barrel and our black nitride bolt carrier group that is finished with an incredible polish, making the action smooth and easy to keep clean.


  • 16" 5.56 4150 CMV Barrel - Black Nitride
  • M4 Carbine Profile - .750" GB Journal
  • 1:7 Twist Rate - 1/2x28 Muzzle Thread
  • Fitted with A2 Flash Hider

Bolt Carrier Group:

  • Enhanced 9310 Steel (Bolt)
  • 8620 Tool Steel (Carrier)
  • Bolt is shot Peened and MPI
  • All BCG components pre polished before being processed and then post polished for an incredible shine

Upper Receiver:

  • Machined from a Mil-Spec 7075 T6 Forging
  • Hard Coat Anodized per Mil-A-8625F, Type III
  • M4 Feed ramps


  • 15" Lightweight - Free Float M-LOK

Charging Handle:

  • Forged 7075 Aluminum construction
  • Mil-Spec Type-III Hardcoat Anodized finish

Tactical Sport 6-Position M4 Stock Kit:

This polymer stock is made from impact-resistant, high-strength material.

  • Mil-spec Diameter Extension Tube Made from Aircraft Aluminum with Rolled Threads
  • Built for Heavy-duty Operations with Tightest Tolerance Control
  • Stock Assembly Complete with Action Spring, Buffer Assembly, Tear-drop Ring, and Castle Nut


Bare Necessities AR15 Complete Lower Parts Kit:

With everything you need for a complete lower, including every spring, pin, the BN LPK makes your rifle truly complete by including the all-important Safety, Mag Catch, Hammer and Trigger, Take Down, and A2 Standard Grip. 


  • Disconnector Spring
  • Hammer Pin & Trigger Pin
  • Selector
  • Selector Spring
  • Selector Detent
  • Magazine Catch
  • Magazine Catch Spring
  • Aluminum Magazine Catch Button
  • Bolt Catch
  • Bolt Catch Detent
  • Bolt Catch Spring
  • Bolt Catch Roll Pin
  • Take Down Pin Take Down Detent
  • Take Down Detent Spring
  • Front Pivot Pin
  • Front Pivot Pin Detent
  • Front Pivot Pin Detent Spring
  • Aluminum Trigger Guard
  • Trigger Guard Roll Pin
  • Buffer Retainer Detent
  • Buffer Retainer Spring
  • A2 Pistol Grip
  • Pistol Grip Screw
  • Pistol Grip Lock Washer
  • Trigger
  • Trigger Spring
  • Hammer
  • Hammer Spring
  • Disconnector
*May come with standard “tear-drop” endplate OR ambidextrous sling loop endplate based on component availability.
*This product is manufactured based on parts on hand. It may feature a standard or oversized trigger guard, depending on what we have available at the time. Also, it may have a standard curved trigger or a flat trigger.*

Flat or Straight Trigger

Please Note: Uppers may present light fouling from our quality control process and/or test firing