HK MR556A1 Specifications:
- Caliber: 5.56 NATO
- Length: 33.68 – 37.68 inches.
- Barrel Length: 16.5 inches
- Barrel Twist: 1:7 inches, 6 lands/grooves
- Operating System: Short Stroke Gas Piston
- Sights: No Sights, Optics Ready Picatinny Rail
- Trigger Pull: 7.64 pounds
- Weight: 8.6 pounds
- Handguard: M-LOK Compatible
- Stock: HK Telescoping
