Nikon made 6x40s, and discontinued them IIRC, they are around. Had one...
Good bullets thru Vitals = a Proven Formula!
Game knows NOT - headstamps, MV, FE, KO, or Ballistic Gack.
Know YOUR rifle/load/sight in and hold/twist accordingly then S Q U E E Z E
6.5mm's - Dropping Lions, Moose, and Elephants since 1894.