The HK MR556 A4 delivers HK416-derived engineering in a civilian-legal configuration, combining German precision manufacturing with modern tactical features. This 5.56x45mm rifle features an 11-inch threaded barrel and distinctive Patriot Brown Picatinny rail receiver that sets it apart from standard black configurations.
What Makes This Different
Built on HK's proven gas piston operating system rather than direct impingement, the MR556 A4 runs cleaner and cooler under sustained fire. The proprietary HK gas system reduces fouling in the action by 75% compared to AR-15 platforms while maintaining the familiar ergonomics and manual of arms. Cold hammer-forged barrel construction delivers consistent accuracy across temperature extremes and extended firing schedules.Key Features
- HK proprietary short-stroke gas piston system for enhanced reliability
- 11-inch cold hammer-forged barrel with 1:7 twist rate and threaded muzzle
- Patriot Brown anodized Picatinny rail receiver with full-length top rail
- Free-floating M-LOK handguard for accessory mounting flexibility
- Ambidextrous safety selector and magazine release controls
- 6-position collapsible stock with multiple length-of-pull adjustments
- 30-round polymer magazine included with purchase
Technical Specs
- Caliber: 5.56x45mm NATO/.223 Remington
- Barrel Length: 11 inches, cold hammer-forged with 1:7 twist
- Overall Length: 28.5-31.5 inches (stock collapsed/extended)
- Weight: 8.6 pounds unloaded
- Magazine Capacity: 30+1 rounds
- Operating System: HK proprietary short-stroke gas piston
- Receiver Finish: Patriot Brown anodized aluminum
- Handguard: Free-floating M-LOK compatible
- Stock: 6-position collapsible synthetic
- Safety: Ambidextrous selector
- Country of Origin: Germany/USA