Similar to the 5.56mm rifle, the MR762A1 is a direct descendent of the HK416/417 series, and only in a semi-automatic rifle configuration developed for civilian users. Using the HK-proprietary operating system, the MR762A1 is gas operated and uses a piston and a solid operating "pusher" rod in place of the common gas tube normally employed in AR15/M16/M4-style weapons.
With both the HK modular rail system and the free floating rail system, the barrel does not touch the handguard, ensuring the barrel/handguard relationship is truly free-floating for maximum accuracy. The MRS handguard was added in 2016 and has many of the features found on the FFRS but with a more ergonomic design. It uses an HK proprietary keyhole design to allow the attachment on Picatinny rail segments to the handguard for the installation of accessories.