•  Site Menu
Self DefenseBrowse self-defense products at ArnzenArms
CompetitionBrowse competition products at ArnzenArms
HuntingBrowse hunting products at ArnzenArms

Login or register for FREE SHIPPING on all orders over $300!

Check here for current AMMO availability at our Eden Prairie location.

Heckler and Koch / Upper receiver

  • Sort by Price
  • Low to High
  • Heckler and Koch
  • Upper receiver
  • Clear all

Show search filters

Hide search filters

  • In store
  • Online
  • Include out of stock
  • (clear) Remove Other filter Other
    • (clear) Remove Parts filter Parts
      • (clear) Remove Upper receiver filter Upper receiver

Heckler and Koch firearms are considered by many to be the finest military grade weapons available to the public.

HK MR556A1 Complete Upper Receiver, 223 Remington/556NATO, 16.5" Cold Hammer Forged Barrel, Black, M-Lok Free Float Rail, Flash Hider, Complete MR556 Bolt Carrier Group, Proprietary Tungsten Buffer, Proprietary Buffer Spring 81000584

MR556A1 Complete Upper Receiver
Out of stock. Check back later...
$1,925.00
MR556A1 Complete Upper Receiver

HK MR556 A4 Upper Receiver, 223 Remington/556NATO, 16.5" Barrel, Threaded 1/2X28, M-LOK Handguard, Anodized Finish, Black, Fits AR-15 Lower Receivers, Includes Bolt Carrier Group, Charging Handle, Buffer Weight and Buffer Spring 51000384

MR556 A4 Upper Receiver
Out of stock. Check back later...
$2,220.00
MR556 A4 Upper Receiver

HK MR556 A4 Upper Receiver, 223 Remington/556NATO, 11" Barrel, Threaded 1/2X28, M-LOK Handguard, Anodized Finish, Black, Fits AR-15 Lower Receivers, Includes Bolt Carrier Group, Charging Handle, Buffer Weight and Buffer Spring 51000385

MR556 A4 Upper Receiver
Out of stock. Check back later...
$2,220.00
MR556 A4 Upper Receiver

Filter your search

  • In store
  • Online
  • Include out of stock
  • (clear) Remove Other filter Other
    • (clear) Remove Parts filter Parts
      • (clear) Remove Upper receiver filter Upper receiver

Buy Now, Pay Later with Credova - Get approval with no credit impact

 
Brands
Guns
Ammo
Other
About us
Contact us
Policies
Blog
New arrivals
FFL transfer
Gift cards
Clearance

© 2013 - 2025, ARNZEN ARMS LLC; all rights reserved.
Phone: 952-944-1875
12494 Plaza Dr, Eden Prairie, MN 55344