There is some interesting research by Dan Flowers on rifle cleaning. In essence, he looked at accuracy over the number of rounds and its relationship to cleaning the carbon or cleaning the carbon and the copper from a barrel (fully cleaned). The conclusion was that it is always helpful to clean...
What is your shooting position? A lightweight rifle with a stout round typically needs the forend held (as in the prone position for the across the course shooting or in typical sling shooting positions) If you are leaving the forend free as in a bipod/rear bag setup (totally different kind of...
I just picked up a Vortex Diamondback Tactical FFP 6-24 x 50 with EBR-2C (MOA) reticle for $359.99. Other scopes mentioned are good, but I have found this to be the best for long range shooting (in this price range) that is simple and allows fast follow up shots.