PPS Kar98k/Type 24 adjustable fps broken

I have a PPS Type 24 and the screw that adjusts the fps in the nozzle is a bit fucked. By that I mean that it turns freely and will not screw in or out. I can't even get the screw out of the nozzle to replace it. Does anyone know where I can get pps kar98/Type 24 parts from?

It still shoots but as the screw is almost all the way open its rediculously high fps. I just need to be able to adjust the screw.