Hi, I have always wondered, what is the exact right position and angle for a weapon to be in an FPS? Some games have it more to the centre than others and some have them further away and some closer. So, what is the precise distance, position, and angle that a weapon is supposed to be from the camera?
Whatever looks the best! Some games use the weapon as a part HUD, and so they are more prominent. Experimentation will give you an idea what works best for you.
If you want to be really cool you can make the weapon track an empty that is cast to the hit position of a ray cast from the center of the screen. That way it will always aim at the location the bullets will hit.
What Rubbernuke said, and I say: Golden Ratio.
The Angle definitely is a Matter of what looks best for each Weapon, though by default you should consider the Weapon oriented straight ahead. (edit: or what AniCator said)
Concerning the Positioning however: Ø Golden Ratio
Position:
[.......|.......] (Screenwidth)
[.......|....:..] (Half Screen Golden Ratio)
[.......|..:....] (Whole Screen Golden Ratio)
.:X:. (Average Position)
EDIT: So much mathemartistic Blabbering for just saying: Centered in the right Half.