Well I would say in my opinion that first off keep both If you raid I can see thst first in last out being good for skolas especially if you out boss spec on it However your xenoclaust is gonna be better I think since vorpal is only for bosses, and vehicles in pve, one y are you running up to a boss to shotgun, and two there seems to be very few vehicle combatants, I know it works on cyclops and hydras, and obviously pikes and stuff like that, but they are not very abundent So for me I would keep the xeno for regular pve but keep the first in last out if you want for skolas, I can't see it being much more helpful, maybe in pvp but I don't suggest trying to shotgun a super, it's likely gonna take two shots and before you can fire again ur likely gonna die just cause of all the area affect damage most supers do