It just uses the bolt and barrel out of the Suomi kit. I had also thought about building it so it would take the suomi mags and drums. All you would have to do is put a suomi style magwell on it. On that gun it should be easier to get the suomi style magwell on the gun as you don't have the takedown feature to contend with. I am also going to try and use the original barrel shroud on my sgn-9 build. I got two kits both non matching and I am keeping the best parts for a future Suomi build.