I'm still trying to get some more history on this weapon. I spent a long time researching my ANM2. It has a 28yr period, where, there is no record of it. Maybe some day I will find out, just like this S&W 76.
But on a seperate question, What is the ammo that your MK likes the best ? I need to start stocking up, because I do like to shoot my NFA guns once in a while.