Pve only damage bonuses by class for the special weapons. Here's the what and why: Hunter/Sniper rifle: Makes sense. Hunters snipe, because they hunt. Warlock/Fusion rifle: Warlocks are magical, fusion seems pretty magical. It's a good fit. Titan/Shotgun: Titans are supposed to be able to take more damage, seems logical they have to use shotguns because of that. Remember, this is pve only. Doing this in pvp would be insane. Bump or like if you want your guardian to kick more ass.