A member on another board I frequent picked one up who lives down south. It works, but in a pistol he said he has to do some tweaking with it. It requires an M16 bolt carrier and heavy buffer:
View: https://youtu.be/v4lncq-1FXA
View: https://youtu.be/VrGflHK5dPY
View: https://www.youtube.com/watch?v=k7QzGs6EXqI
A great video with a 9mm upper beltfed at the end:
View: https://www.youtube.com/watch?v=Cuougs2GmGA
Guy in the first 2 vids must be afraid of muzzle rise cause he mag dumps into the ground 10 feet in front of him. Lol