Home / AR Rifles / Heckler and Koch
Heckler and Koch MR556 A4 Patriot Brown 5.56 16.5 Barrel 10-Rounds

Specifications

Model
Series
A4
MPN
81001204
UPC
642230271081
MSRP
$4,299.99
Action
Semi-Auto
Barrel Length
16.5"
Capacity
10 Rounds

Description

HK MR556 A4 Features This rifle incorporates a cold hammer-forged steel barrel with a 1:7 twist rate and six-groove rifling offering durability and precision for a variety of bullet weights. The threaded muzzle with a 5/8x24 pattern allows for easy suppressor or muzzle device installation while the full-length Picatinny rail provides optimal optic placement and accessory attachment. The trigger pull weight ranging from 4.5 to 5.6 pounds ensures smooth and consistent operation. The MR556 A4 is engineered with an ambidextrous safety making it ideal for both left- and right-handed shooters. The rifle also features a robust polymer stock and grip paired with a durable anodized handguard that supports accessories through the M-LOK interface. Whether for precision shooting or tactical use the MR556 stands out as a versatile and rugged option. HK MR556 A4 Specifications Brand: HK Model: MR556 Series: A4 Category: Tactical Rifles Caliber: 5.56x45mm Action: Semi-Auto Operating System: Gas Piston Capacity: 10 + 1 Max Capacity: 10 Barrel Length: 16.5 Barrel Description: Threaded Barrel Material: Steel Barrel Finish: Black Twist Rate: 1:7 Grooves: 6 Thread Pattern: 5/8x24 Muzzle: Threaded Receiver Description: Picatinny Rail Receiver Finish: Patriot Brown Receiver Material: Aluminum Handguards: M-LOK Handguard Finish: Black Stock Description: 6 Position Stock Material: Synthetic Stock Finish: Black Overall Length: 36.5 Height: 7.5 Width: 3.07 Weight: 7.67 lbs Trigger Pull Weight: 4.50-5.60 lbs Safety: Ambidextrous Safety Lever Sights: None Hand: Ambidextrous

Other AR Rifles

Stay Connected

Join our newsletter for the latest updates and exclusive deals.

ARMSAGORA

Compare prices on firearms, ammunition, and accessories from hundreds of trusted retailers. Find the best deals, track prices, and build your own loadouts.

© 2026 ARMSAGORA. All rights reserved.
Not an FFL licensed dealer. ARMSAGORA is a free product comparison tool. Some links to retailers are affiliate links: we may earn a commission when you buy, at no extra cost to you.