I was in Florida last week and picked up a Mosin Nagant 91/30 that had been turned into a sniper. I had been looking at them on the SOG (Southern Ohio Gun) website, but felt being able to hug squeeze and love it (and not having to clean cosmoline off it) made it a better buy, plus the price was actually less than their "dealer" price.
It is a 1939 dated Tula (?)
I haven't gotten to the range yet, but I noticed that the scope crosshairs are canted to about 9 oclock 4 oclock so you would hold the rifle at an angle if you had the cross hairs level.
I sighted on a distant flower with both the iron sights and the scope and it appears that if I sight first with iron sights and then without moving look through the scope the scope is off (when the rifle is level) but if I sight the scope with the horizontal cross hair level and the rifle angled when I look through the iron sights they are on the flower.
Could this have been done by a previous owner to put the bullets on target?