Russians did use meters back then, but it doesn't really matter.
I'm an American so I use Yards.
I developed a load where my M91/30 is zeroed at 100 yards while set on the 100 mark. It works on the other markings (up to 400 yards which is the max I have on my back yard range).
Meaning, when sighted in at 100, its also good for 200 yards on the 200 mark, 300 on the 300 yard mark, etc, etc.
I use reloads, I don't shoot any of that surplus stuff so I can't tell you what they will do.