H&K MR556 A4 5.56mm AR Pistol, Black

The H&K MR556 A4 is a black semi-automatic AR pistol chambered in 5.56mm. It combines a short-stroke gas piston operating system with a threaded barrel, M-LOK handguard, Picatinny rail, and ambidextrous controls.

An adjustable gas regulator supports configuration for suppressed or unsuppressed operation, while the optics-ready design provides a flexible platform for compatible sighting equipment. One 30-round magazine is included.

Key Specifications

• The chambering is 5.56mm for compatibility with the listed cartridge designation.
• The operating system is a short-stroke gas piston design.
• The action is semi-automatic for individual shot operation.
• The finish is black for a consistent exterior appearance.
• The handguard features M-LOK attachment slots.
• The receiver includes a Picatinny rail for compatible accessories.
• The controls include an ambidextrous safety and magazine/bolt release.
• The barrel is described as threaded and uses a listed 1/2×28 thread pattern.
• The package includes one 30-round magazine.
• The product is listed as optics ready in the supplied specifications.

With its piston-driven operating system, adaptable gas regulation, modern mounting interfaces, and fully ambidextrous controls, the MR556 A4 offers a carefully configured platform for owners seeking established H&K design and practical configuration flexibility.

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