In Stock
HK MR556 A4 AR-15 Complete Upper Receiver 5.56x45mm NATO 16.5" Barrel
Sold byMidwayUSA•Posted Apr 27, 2026
Compare prices for HK MR556 A4 AR-15 Complete Upper Receiver 5.56x45mm NATO 16.5" Barrel$2,179.00
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Deal Summary
- Currently in stock.
- Caliber: 223/5.56
- Category: parts
- UPC: 642230270213
- SKU: 220277
- Brand: Hk
Price History
Deal Details
This kit includes a complete upper receiver/barrel assembly, allowing Mil-Spec 5.56mm AR-style rifles to be retrofitted to HK's piston and pusher rod system. This system utilizes a piston and a pusher rod in place of the gas tube normally found in AR15/M16/M4-style rifles. This closed system virtually eliminates the malfunctions that are common in direct-impingement gas systems, since hot carbon fouling and waste gasses are not propelled into the receiver area to operate the action. This is the
Other Offers for This Product
Active offers from your catalog for HK MR556 A4 AR-15 Complete Upper Receiver 5.56x45mm NATO 16.5" Barrel.
Comparing 6 retailers carrying this product
Lowest Price: $1,993.00
Highest Price: $2,179.00
You Save: $186.00
Avg Discount: 6% off
HK 51000384 MR556 Upper Rcvr Kit 5.56mm for AR15/M16/M4,Upper
Heckler & KochHinterland OutfittersSKU/UPC: 235036
$1,993.00
View at Hinterland Outfitters
HK USA MR556A4 Upper Receiver Kit 5.56 NATO 16.5"
Hk UsaKYGUNCOSKU/UPC: HCK-51000384
$2,059.65
View at KYGUNCOHK MR556 A4 AR-15 Complete Upper Receiver 5.56x45mm NATO 16.5" Barrel
HkMidwayUSASKU/UPC: 220277
$2,179.00
View at MidwayUSA
HK 51000384 UPPER RECEIVER KIT MR556A4 16.5
Heckler & Koch, Inc.BattleHawk ArmorySKU/UPC: 642230270213
$2,179.00$2,499.00Save 13%
View at BattleHawk Armory
HK UPPER RECEIVER KIT MR556A4 16.5''
Heckler & KochOptics PlanetSKU/UPC: 13-UPK-51000384
$2,179.00$2,499.00Save 13%
View at Optics Planet
Heckler and Koch MR556 A4 Upper Receiver 5.56 16.5 Barrel
Heckler And KochGrabAGunSKU/UPC: GAG_51000384-178700
$2,179.00$2,499.00Save 13%
View at GrabAGun