M-24s one-shotting my colonists through power armor?

[Morrigi]

Well, pirates with M-24s appear to be able to one-shot my colonists, even if they're wearing power armor. Yes, I checked where the shots hit, and they were to the torso.

Considering that the M-24 is chambered in 7.62x51 NATO, and that 7.62x51 ball ammunition can be stopped by even modern NIJ level III ceramic or AR500 steel trauma plates, this doesn't make a whole lot of sense, unless the pirates are packing ridiculous future lolammunition.
This is occurring in version 7b.