If you look at spent primers through a microscope you'll find all kinds of weird stuff. Unless there are high pressure signs (which you wont get from Winchester 180 7.62X54R factory rounds), as long as the primers go off you're good to go.
Try shooting your ammo in another Mosin and you'll see something different.
With pistols its fun. When we shoot matches all the brass is piled on the table so we can get our brass. You can instantly look at 9mm brass and tell what came from a Beretta and what came from Glocks and M&Ps.
Its actually fun to examine brass and try to determine what gun it came from.
I know you said you wanted the link closed, but I thought I'd throw this in, skipping the unrelated range bit.
