Like its 5.56 mm counterpart, the MR762 is a direct descendent of the HK416/417 series, only in a semi-automatic rifle configuration developed for civilian users.

Using the HK-proprietary operating system, the MR762 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. Pioneered by Heckler & Koch in the G36, HK416, and HK417; this method virtually eliminates malfunctions common to direct impingement gas systems since hot carbon fouling and waste gases do not enter the receiver area. The MR762 stays cleaner and heat transfer to the bolt and bolt carrier, and wear and tear on critical components is drastically reduced. The service life of all parts is increased substantially

The MR762 uses a barrel produced by Heckler & Koch's famous cold hammer forging process. This manufacturing process uses the highest quality steel, producing a barrel that ensures superior accuracy, even after firing 20,000 rounds.

The MR762 will be produced at Heckler & Koch's new manufacturing facility at Newington, New Hampshire from both American and German made components.

The MR762 uses many of the assemblies and accessories originally developed for the HK416/417 series including adjustable buttstocks, ergonomic pistol grips, mechanical sights, and the HK free-floating four-quadrant rail system/handguard. This MIL-STD-1913 “Picatinny” type rail system allows all current accessories, sights, lights, and aimers used on M4/M16-type weapons to be fitted to the MR series. The HK rail system can be removed without special tools by the user and ensures 100% return to zero when reinstalled.??

Ambidextrous operating controls are standard on the MR762, including the charging handle and an ambidextrous selector lever. The MR762 also uses the same 10- and 20-round translucent polymer box magazines made for the HK417.

Production delays will prevent Heckler & Koch from meeting its delivery schedule on both the MR556 and MR762 rifles introduced at the 2009 SHOT Show in Orlando. Aside from finalizing the manufacturing process, HK engineers and technical staff in the U.S. and Germany are using the time to refine elements of the design, improve the quality of the rifles’ components, and ensure the final product is consistent with HK’s highest standards.