Mosins are not super scope friendly unless you already have one that was set up as a sniper rifle. The military sniper rifles were picked from production rifles that showed better accuracy and then the receivers and stocks were modified to accept a scope. The WW2 scopes were low power and small as far as diameter goes and dud not have the best light transmission or clarity. Functional, yes, but not spectacular.
If you want a properly scoped one save up and find one of the snipers that had a scope with it.