For your desires, I would look for a Zeiss Conquest. You should be able to find a 4.5x14x40 in that price range, and it would be an optical leap above the Buckmaster. Unless you're looking to get into the LR game, I don't know that you need all the bells and whistles--and expense--that comes with choosing big turrets and complicated reticles.
Another scope that I think provides good value is the Weaver Grand Slam in that price range, but the WGS in 4.5x14x40 is a little too bulky and heavy for my likes. I prefer the 3.5x10.
FWIW, my "carrying" .300WM, a Winchester 70 FWT with a custom Douglas sporter barrel, wears a Conquest 3x9x40. My "heavy" .300WM, a trued Rem 700 with a Jewell trigger and fluted Krieger bull barrel, currently sports a Vortex PST, but for years wore a heavy (and obsolete) Burris Signature 6x24x40.
"For every complex problem there is an answer that is clear, simple.....and wrong." H. L. Mencken