It was the AAC 77gr TMKs, but I'll shoot if again just for you
I put the 1/2" red dots I shoot at 100rds on the boxes of ammo that don't work out, it also hated the 69gr AAC SMK's
When I take the 18" SPR out for load development I'll shoot every type of factory 5.56/.223 ammo I have on hand so y'all can see what she like and hates.
Keep in mind the AAC stuff isn't what I'd call consistent.