This is when it pays to be patient. If you're in a hurry, you might as well find a good new rifle and buy that, because finding a good used rifle suitable for your purposes can take some time.
My advice here is, when you find a manufacturing lot of these calibers, that your rifle shoots well, buy all of that lot that you can afford to in preparation for the day ...
The base is the part that attaches to your rifle, while the ring (or rings) is what you insert and secure your scope into. The majority of rifles on the market today come with predrilled holes for ...