VFC MP5 bolt disassembly issue

[Strelok]

Hey there.

Fucked up a part trying to replace a formerly broken one. Go me.

Anyway, i'm looking to disassemble the entire bolt so I can replace the loading nozzle and cylinder (which I just recently broke.) but the front half of the bolt doesn't seem to want to twist off.

I've removed the set screw in the back, and the c clamp that holds the spring. Am I missing anything else here? Help would be appreciated.

Thanks