Looks like the rear-end of a standard WWII German MG42 that was subsequently "re-numbered"....possibly by Rusia or any of several other nations that obtained these after WWII.
....or were you loooking for who made this by the Waffenampts (?).
The "code" is for DOT .
The "1928" was the original German Serial-Number for this MG34........later, as parts were "forced-matched", some owner used either another part's serial number (such as a different barrel-jacket) as the starting-point while piecing an MG34 together from parts/assemblies......they then stamped the new serial-nubmer onto the rear of the receiver and "lined-out" the old serial number.