Professor Parabellum's HSTS UNW Adjustable Buttstock

I can’t test fit this but the main components are the same as the tested FGC-9 one so it should be alright… see the manual of the FGC-9 edition for the installation. for a big part will it be the same.

there is a DC buttstock added. this means Dust Cover. once the buttstock is fully forward. will it cover up the open section of upper