I have suddenly found myself very interested in the fmk 3 and parts kits are plentiful. the recoil spring isnt behind the bolt so this would make a hammer or striker setup alot easier. BUT theres not many detailed pictures on the web. If anyone here has a parts kit I would really apreciate some close up pics of the bolt from several angles and some pics of the lower receiver from a top view and also how does the barrel nut attatch? is the receiver threaded at the front?