The recent update made think of AP as a vanity item now. I didn't use it much against undead after i've got pulsar but i found it pretty effective for fighting fiends. AP had it all: high speed of bullets, larger clip size, increased damage vs fiends because of piercing part of damage and it allows moving while shooting! AP was an excellent choice for Dark City levels as it was doing increased damage to all of its denizens.
Now after update AP is ruined for me, it's useless and i have nothing to replace it with. Callahan has only 2 shots per clip which devilites easily avoid and both needle shot's lines don't allow moving while shooting as any autogun which makes you easy target.
I think AP's damage either need to be reverted back to Elemental/Piercing and new pure elemental line added if the need for it really exists (i personally think it doesn't) or Antigua should get additional pure piercing line. We need guns to fight fiends too.
Why do you think it wouldn't be a fiend killer now? I mean, it's not like it's dealing shadow damage. It's still really fast and accurate and probably harder for them to dodge. Just because you don't get a damage bonus doesn't make it a bad gun.
But now it's a perfect thing for fighting spookats and constructs and I can't wait to have one myself.