Hello, I am interested in getting a scope for my Mosin-Nagant 91/30. The problem is that I really don't know anything about scopes(super noob). I would remove the rear sight and place the scope there on a mount. The current scope I am looking at getting is a 4-12x44mm scope. From what I have read different scopes require your eyes to be within a certain distance from the sight to get a clear view. I think the term I'm trying to get at is "eye relief." So do you think I could use a 4-12x44mm scope on a very long gun like the 91/30. Thanks for any help.