Yeah. In-lore power armor has got the durability of a tank. That doesn't mean it's invulnerable. Just needs rounds designed for piercing.

Also vulnerable to EMP, hence why pulse rounds are also effective against them.

It depends on the armor type, t 40 and 51 b will get killed by that t 60 will stand a slight chance, and t 65 would be perfectly fine, hellcat would be unaffected, and x01 wouldnt be affected aswell