This mod from Cody Knutson changes the shotgun into a sawed-off version.
Author: Cody Knutson
This is an alternate model for Doom 3. Form of sawed off shotgun.
put supershotgun.pk4 file in your Doom 3base folder
run game and start map. Bring down console and type "give weapon_supershotgun"
Feel free to use this model for whatever. Doesn't matter to me.