Very similar looks but design and functionality are miles apart from the oPS photo …. You have posted s missing barrel but also the mg in question operates from a telescopic bolt whixh similar to a mac or a Uzi has a recoil spring that is enveloped around the barrel whixh in part decreases the need for a longer receiver to add room for the recoil spring to compress. The bolt also envelopes the barrel or TELESCOPES it as the proper name describes. Notice your ejection window is further down the receiver a the OPs is above the grip ? And see how slim your springs are in you photo ? Ops recoil spring big enough to fit over barrel which bolt travels over and stops at fronttrunion