Interesting sample of weaponry. Spanish historical automatic pistol. Interesting barrel fixation, smooth shape and internal hammer. Was created using some exploded diagrams, photos and schematic views. As usual we started with the cartridge and barrel through slide and then it all became more familiar.
The thing is, you start with basic shape of moving parts and try to fit them all each to other using some basic animations and lot of experience. Only after that we start to make them look real.