the mosin nagant is one of the crudest designs in history. the tool marks are ugly, the bolts are stiff, the handles are too short to offer any real leverage and the leaf sights are horrible. add to that, the fact that the soldiers that used them were uneducated, untrained conscripts, trying to 'wing it' when it came to maintenance so bores were carved into ovals by steel cleaning rods. add shot out oval bores, crude designs and then the fact that most ammo you can get is either inaccurate and corrosive surplus or just plain inaccurate wolf/tula and it's THEN you want to put a tacticool sniper stock on it?
I don't really know what you expect from a rifle designed in the 1800's that was mass-produced by the millions.
The rifle works well and it shoots a very capable round. It was given to mostly untrained soldiers so MOA accuracy was not required since they cannot shoot it to begin with. you cannot expect it to be as nice as a $1k+ Remington 700...