Leupold been making below scope for few years 6x42AO and I have that on one of my varmint rifles been a good scope solid everything track greats but it's pretty expensive compare to the others.
http://www.leupold.com/hunting-shoot...x42mm-adj-obj/
I have two early Leupold 6x compact with AO, one I left original other I had target knobs and dot install both are good scopes.
Fixed powers I like AO's. Another good 6x is the older Weaver T-6 steel tube and you can find them in the $200 to $250 range and they been holding their value.
Well good luck