The MR762A1 from H&K is a 7.62×51 (.308 Winchester) descendent of the HK416/417 series, a semi-automatic rifle for civilian users. This system uses a solid “pusher” rod instead of the gas tube on a standard AR, and this makes the system very clean, because gas never gets into the receiver. It takes HK417 mags, and as you can see from the video, there are a number of features built into this rifle that make it more sure and stable than a standard “legacy rifle” AR-platform configuration.