H&K MR556A1 5.56mm Rifle, M-LOK Handguard w/ 16.5" Barrel Overview The H&K MR556A1 is the civilian descendant of the legendary HK416, engineered to deliver exceptional reliability, durability, and match-grade accuracy. Featuring Heckler & Koch's proven short-stroke gas piston operating system, a German cold hammer-forged barrel, and a free-floating M-LOK handguard, the MR556A1 offers premium performance for discerning shooters. Built using American and German components, this rifle combines military-inspired engineering with precision-focused enhancements for competition, training, and defensive applications. Key Features a HK short-stroke gas piston operating system for enhanced reliability and cleaner operationa German-made 16.5" cold hammer-forged barrel with 1:7 twista Free-floating M-LOK handguard for improved accuracy and accessory mountinga Enhanced two-stage trigger for precision shootinga Flat-top Picatinny upper receiver for optics and accessoriesa Retractable adjustable stock with locking featurea Extended charging handle latch for easier manipulation with optics installeda Heavy-profile, non-chrome-lined barrel optimized for maximum accuracya Compatible with many standard AR-style upper receiver componentsa Manufactured in the USA using American and German components Specifications a Manufacturer: Heckler & Kocha Model: MR556A1a Manufacturer Part Number: 81000579a UPC: 642230262553a Caliber: 5.56 NATO / .223 Remingtona Action: Semi-Automatica Operating System: Short-Stroke Gas Pistona Barrel Length: 16.5"a Barrel Twist: 1:7"a Overall Length: 33.90"-37.68"a Weight: 8.6 lbsa Receiver Material: Aluminuma Handguard: Free-Float M-LOKa Stock: Adjustable Synthetica Grip: Black Polymera Trigger Pull: Approximately 7.64 lbsa Sight Radius: 14.6"MPN: 81000579 UPC: 642230262553 Applications The MR556A1 is ideal for precision shooting, competitive events, tactical training, home defense, and recreational range use. Its piston-driven operating system and premium barrel make it an outstanding choice for shooters seeking maximum reliability and accuracy from an AR-style platform. Additional Features a Based on the battle-proven HK416 design trusted by military and law enforcement professionalsa C.I.P.-spec chamber supports reliable operation with 5.56 NATO and quality .223 Remington ammunitiona Heavy-contour barrel features a slight internal taper to enhance velocity and accuracya Free-floating barrel eliminates handguard contact for consistent shot placementa Upper receiver assembly can be used to retrofit compatible AR-style rifle platforms Magazine not included.