I started another thread about putting a scope on a Ruger 10/22. (big thanks to those that responded). BUT... As I mentioned in the thread I've never had nor know anything about scopes. Sooooo if someone has the time I could use a little education. BTW, will be used to shooting paper, tin cans, plastic and other assorted things that don't move as I sneak up on them. A scope that was recommended (more than once) was a Nikon 3-9X40 BDC. I use this as an example as it had the most numbers and letters. What does the 3 stand for, The 9X40 and the BDC? I was also offered a 6X what does this mean vs the 9X40? Why or what makes a scope rim fire specific over any other scope? Any help is really appreciated. It's hard to make decisions when I don't even know what I don't know.