Since the OP mentioned budget constraints in his post here goes -
223 brass - dirt cheap and tons of it, quite often available just for picking it up.
223 vs. 22/250 powder charges - generally speaking the 22/250 uses about 1/3 more powder than the 223, which means that with a 223 every third can of powder is a freebie.
The 223 and a 40 gr bullet at 3800 fps is a magic combination on everything from gophers to coyotes.
Personally I am ok with a 10 power scope for varmint shooting, about the only time I am above 10X is for load development when I am shooting paper.
Forget the tactical rings and picatinney base - they will gain you nothing and probably cause difficulty getting a good cheek weld due to the increased height. Weaver bases have worked for over 60 years, get a set of Burris Signature Zee rings to go with them and you are good to go.
drover
