Besides this being a proof of concept, would you really use this model for a FPS?
From what I've found on StackExchange and Blender forums, all models used in a first person perspective are animated. Showing animations like firing, reloading, chamber checks, fire selecting, etc. From what I've gathered all models used for work like that are multi-piece models. Such as so that if this pistol were to be given a reload animation, that magazine, slide, and frame would be seperate pieces, and have separate bones in the animation. How would you model that? Or would you just make the models and mush them together so the magazine would clip into the frame?