FPS Camera question

If you've got just the weapon and camera, and no player character? I'm not sure it matters all that much. Although you might want to have the weapon attatched to the camera, as it's probably easier to conceptualize a camera having a bounding box/sphere/whatever you use for collision, than just a weapon.

Unless you'll be creating a basic 'Player' class that contains only a camera and weapon, without a player model and just have the Player class contain the bounding information.

The best way to do it is probably to have the movement controls move the camera, then position the weapon from the camera's View matrix. Or you could always just overlay a 2D sprite, assuming you didn't want to light or shadow it dynamically.

-Chris