Is there any "official reason" why the PKM has never gotten any form of AP ammo?

Through my somewhat limited research I found a few things: Cold war doctrine states the SVD gunner in the squad is that; a member of the squad, which is why the SVD has a bayonet lug, if the squad participates in a bayonet rush the SVD gunner will participate, that being said leadership in the Soviet Union in an effort to simplify logistics issued 762x54R to be used with interchangeably between SVD & PKM gunners.

In-game the SVD can use 7BZ3 API, therefore the PKM should also be able to use it. (if not even just regular AP).