Can confirm--this happened to my friend after he left and rejoined a server.

Confirmed. There is virtually no use for the Mosin in the current state of the game, as you can only "zero" your long range scope by taking an educated guess, or killing a zombie. Obviously if you've been to an area you shot at before, the ranges don't change but if you encounter a new area or are in a new firing position, you NEED to be able to see your shots in order to adjust.

Sticking with the M4 until this is fixed </3

So imagine having an ammo box full of 60 stacks of 5.56 ammo in your pants, falling and breaking your leg, and then ruining your ammo box. Imagine how long it took to split ten stacks of ammo down to that one, ruined round.

Headache.