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.

Shopping Cart
Questions & Answers
Is this compatible with a full auto BCG? I’ve heard this was somehow not compatible with a FA BCG.

the bcg is not m16 cut is just off by a little and you can't install a 416 carrier because the the barrel extension has a tab protruding that will prevent it from closing. so it's semi auto all the way.

by Gerry, Verified Owner, January 21, 2021
is this compatible with my truglo red dot? Expert Answer

If your red dot has a picatinny mount then this will be compatible.

by Nick B., Gear Expert, November 16, 2021
Customer Reviews
Helpful Positive Review Everything I expected and more by Chris Goebel, Verified Owner, October 7, 2020
High quality upper kit... obviously. Comes with a buffer and buffer spring, soft case, manual, and m-lok hand guard with QD mounts. I ordered the traditional HK quad rail for this. Shoots very well on an aero lower. I am going to build a BRN4 lower ...
Read More...
1/2 found this helpful
Read 1 Review

Product Discontinued by Manufacturer

Heckler & Koch MR556-A1 Complete Upper Receiver Kit has been discontinued by Heckler & Koch and is no longer available. Our product experts have helped us select these available replacements below.You can also explore other items in the Gun Parts, AR 15 Parts, Rifle Parts, AR15 Upper Receivers yourself to try and find the perfect replacement for you!

ATTENTION! Due to the configuration of products on this page, we are not able to support sales of these items to AK, CA, HI, IL, NY, WA, P.O. Boxes, and U.S. Territories.

Product Info for Heckler & Koch MR556-A1 Complete Upper Receiver Kit

Includes MR556A1 upper receiver/barrel assembly with 16.5 inch cold-hammer forged barrel, free floating rail system handguard, complete bolt carrier assembly, HK proprietary buffer, recoil spring and is designed to be fully interchangeable with most high quality AR-style firearms. Designed to function with 5.56x45mm ammunition and also cycles most quality .223 Remington ammunition. NOTE: This kit does not work with fixed stock AR-15 rifles.image

Specifications for Heckler & Koch MR556-A1 Complete Upper Receiver Kit:

Mfg Item Num:  235975-A5
Type:  UPPER_RECEIVERS
Barrel Length:  16.5
AR-15 Parts:  AR-15 Parts
Caliber:  5.56mm/.223
Tactica:  Tactical
Finish:  Black
Caliber-Gauge:  .223 REM.
Master Model Header:  MR556-A1 Upper Receiver Kit

Package Contents:

  • Heckler & Koch MR556-A1 Complete Upper Receiver Kit

Ammunition

1–53 / 53
Previous
Next

Related Products to Heckler & Koch MR556-A1 Complete Upper Receiver Kit

Heckler & Koch MR556-A1 Complete Upper Receiver Kit Unavailable & Discontinued Models

List of Unorderable Models

Heckler & Koch MR556-A1 Complete Upper Receiver Kit, 5.56mm/.223 Remington, w/16.5in Barrel, 81000077 , MPN: 235975-A5 , UPC: 642230259300 , Code: 13-UFH-235975-A5
Compare (0)