I have a zci rotary in it now. the original was missing along with the barrel.
It fits, its tight against the gearbox and the foregrip. it definitely aint moving!
I have a concern though. just been doing the googles and it appears that MOST m4 nozzles are 21 point something long.
the one that's in it is a 20.7mm. i wonder if the original owner tried to do things and put in the wrong nozzle.
I mean, the tappet plate was wrong, so why wouldnt the nozzle be.
Ok, back to the drawing board...best go and buy some nozzles...