From the YouTube channel Another Incarnation, a conversion of a Type 81 LMG to 6.5 Grendel DMR rifle.  This was done using a donor barrel from a  Ruger rifle and some kind of fiberglass shell for the stock.  I think they are using a TI No-Drill Picatinny rail mount, but I'm not sure.  Turn on auto-translation for translating the subtitles to English.
I didn't go through the entire video, but an interesting project, kudos on the work involved.  The Grendel round should give a lot better performance at range then 7.62x39 mm.  Anyone build an MCR or WK in Grendel yet?  I remember RWA did a long barreled RWA180B build for a customer a while back.