My first play-through I found my Assault Carbine to be useless, even with Armor Piercing rounds which is -25 DT effect for 5mm. Although my memory may be foggy since it was a while ago, maybe the armor piercing rounds did a good job but I didn't have that many or they performed poorly, I can't remember clearly.
My Survivalist rifle was decent against them, but still struggled to make a dent. I'm contemplating taking the .45 machinegun this time but I'm not sure how it will fair.