A New K31 and a Couple of Questions...(Pic heavy)

[diopter]

As in most military rifles, there should be upwards pressure at the stock tip, otherwise long range accuracy goes down the toilet. Had to fix a couple where some people rasped out the lower barrel tip channel causing horrible accuracy at 300m.
If it's not broken, don't try to fix it.
Shoot it first, ask questions later, if needed.