yeah i hated Enclave Soldiers in 3 just because they have the type of power armor that sends their damage resistance to the loving stars. i just use a Missile Launcher because i don't want to waste ammunition or weapon condition fending off the bastards.
love the damage threshold mechanic in New Vegas but it really doesn't matter for some weapons like the Minigun because 5mm rounds reduce target DT by 5 points so you can just go balls to the walls nuts with that.
EDIT: because the Grunt perk is a thing thanks to the Honest Hearts expansion the Assault Carbine can generally be better if you get the extended magazine mod for it.