Barnes make a 150 TSX FB that will take any game you would tackle with a 303.
Woodleigh has a 174 spitzerSP & 215 RNSP.
Finally a 180-200 gr cast bullet can be pushed at +-2000 fps and will kill any game easily within your 200 yard window. (also at 22RF price shooting).
Probably 95% of my 30 cal and up shooting is with cast bullets dropped from the wonderful NEI molds. I shoot the 308-210 GC with the DD centering band on the front. It can be ordered oversize to fit your 303. Starting at 1950 fps from an 06 M-70 or 30-40 custom High Wall, it will hold 1.5 MOA 5 shot groups to 300 yards.
http://www.neihandtools.com/catalog/index.html
