Mp7 i just saw that guns.ru states:
this gun:
It should be noted that North Vietnamese once produced local copy of the MAT-49, chambered for 7.62mm TT round.
Actually a Scorpion or an Uzi, or a Tec9
or ....just google-stumbled on it - this:
That experimental round can be shot out of a Glock and Sig. Don't have link