Features of the Heckler & Koch MR A4 Series: MR556 A4 & MR762 A4 Rifles [Video]

Heckler & Koch MR A4 Rifle Series
Heckler & Koch MR A4 Rifle Series

Bill Dermody of Heckler & Koch shares that the MR A4 series firearms are inspired by the renowned HK416. The HK MR A4 series rifles are engineered to deliver exceptional reliability and accuracy. Furthermore, they incorporate a short-stroke gas piston system, cold-hammer-forged barrels, and fully ambidextrous controls to enhance performance and user adaptability.

Watch the video for more features of the HK MR A4 series with a more modern ergonomic design and improved comfort and handling.

MR556 A4 Pistol 11″ Pistol
MR556 A4 Pistol 11″ Pistol

MR556 A4 Pistol 11″ Pistol Specs:

  • Caliber: 5.56 x 45mm
  • Overall Length: 26.5 in.
  • Overall Height: 7.75 in.
  • Overall Width: 3.07 in.
  • Barrel Length: 11 in.
  • Picatinny Length: 6.75 in.
  • Weight Without Magazine: 6.61 lb
  • Magazine Capacity: 30/20/10
  • UPC: 642230269439 MR556 A4 Pistol, 11″ barrel, 1-30rd Magazine
  • UPC: 642230269446 MR556 A4 Pistol, 11″ barrel, 1-10rd Magazine

Heckler & Koch MR MR556 A4 Rifle

HK MR556 A4 Rifles Specs:

  • Caliber: 5.56 x 45mm
  • Overall Length: 33.25 in. – 36.5 in.
  • Overall Height: 7.75 in.
  • Overall Width: 3.07 in.
  • Barrel Length: 16.5 in.
  • Picatinny Length: 20.3 in.
  • Weight Without Magazine:   7.67 lb
  • Magazine Capacity: 30/20/10
  • UPC: 642230269408 MR556A4, 16.5″ barrel, 1-30rd Magazine 3999
  • UPC: 642230269415 MR556A4, 16.5″ barrel, 1-10rd Magazine 3999
  • UPC: 642230269422 MR556A4, (CA Compliant) 16.5″ barrel, 1-10rd Magazin

HK MR A4 series, a more modern ergonomic design

HK MR762 A4 Rifles Specs:

  • Caliber: 7.62 x 51mm
  • Overall Length: 35.5 – 39.5 in.
  • Overall Height: 7.75 in.
  • Overall Width: 3.23 in.
  • Barrel Length: 16.5 in.
  • Picatinny Length: 23 in.
  • Weight Without Magazine: 9.84 lb
  • Magazine Capacity: 20/10
  • UPC: 642230269453 MR762 A4, 16.5″ barrel, 1-20rd Magazine
  • UPC: 642230269460 MR762 A4, 16.5″ barrel, 1-10rd Magazine
  • UPC: 642230269729 MR762 A4, 16.5″ barrel, (CA Compliant), 1-10rd Magazine

Heckler & Koch MR A4 features fully ambidextrous controls

What are the Key Features of the MR A4 Series Rifles?

  • Operating System: Both models utilize a short-stroke gas piston system, minimizing carbon fouling in the action for enhanced reliability and reduced maintenance compared to direct-impingement systems.
  • Ambidextrous Controls: The MR A4 series features fully ambidextrous controls, including the safety selector, bolt release, and magazine release, facilitating use by both left- and right-handed operators. ​
  • Adjustable Gas Regulator: An adjustable gas block allows users to fine-tune the rifle’s operation for suppressed or unsuppressed shooting, optimizing performance based on specific needs. ​
  • Barrel Durability: The rifles are equipped with cold-hammer-forged barrels made from cannon-grade steel, guaranteed for life against wear. HK’s testing demonstrated no accuracy degradation after 12,000 rounds, while competitors’ barrels showed significant accuracy loss. ​
  • Ergonomic Design: The MR A4 series includes updated furniture such as a slimline handguard with an M-LOK interface and an ergonomic pistol grip, enhancing user comfort and control.

HK MR A4 series rifles are designed for civilian ownership
HK MR A4 series rifles are designed for civilian ownership

Are These Rifles Suitable for Civilian Use?

The Heckler & Koch MR A4 series rifles are designed for civilian ownership, offering features that closely mirror the military-grade HK416 and HK417 platforms, providing users with high-performance and reliability.

HK MR A4 series, ideal for shooters seeking precision, durability, and versatility
HK MR A4 series, ideal for shooters seeking precision, durability, and versatility

The HK MR A4 series includes the MR556 A4 and MR762 A4 rifles, designed for civilian use with military-grade performance. Built on the legendary HK416 and HK417 platforms, these rifles feature a reliable short-stroke gas piston system, cold-hammer-forged barrels, ambidextrous controls, and modern ergonomic design. The MR556 is chambered in 5.56 NATO, while the MR762 uses 7.62 NATO, making the series ideal for shooters seeking precision, durability, and versatility.

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