In StockSave 13%
Heckler and Koch MR556 A4 Upper Receiver 5.56 16.5 Barrel
Sold byGrabAGun•Posted Apr 27, 2026
Compare prices for HK MR556 A4 AR-15 Complete Upper Receiver 5.56x45mm NATO 16.5" Barrel$2,179.00
$2,499.00
You save $320.00 (13% off)
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Deal Summary
- Currently in stock.
- Caliber: 223/5.56
- Category: parts
- UPC: 642230270213
- SKU: GAG_51000384-178700
- Brand: Hk
Price History
Deal Details
Heckler & Koch MR556 A4 Upper Receiver Features This upper receiver kit includes everything you need for a top-tier build: a bolt carrier group charging handle buffer weight and buffer spring. The 16.5-inch barrel features concentric 1/2x28 threads for suppressor compatibility paired with an adjustable gas regulator to ensure reliable cycling whether suppressed or unsuppressed. The cold hammer-forged barrel is designed for exceptional longevity and match-grade accuracy. The M-LOK handguard
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 5 retailers carrying this product
Lowest Price: $1,993.00
Highest Price: $2,179.00
You Save: $186.00
Avg Discount: 8% 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 OutfittersHeckler 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
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
HK MR556 A4 AR-15 Complete Upper Receiver 5.56x45mm NATO 16.5" Barrel
HkMidwayUSASKU/UPC: 220277
$2,179.00
View at MidwayUSA