Not all 30 cals shoot a light bullet well.

165/168 is a good compromise, plenty for deer, ample on bigger stuff, and generally shoot in most rifles.

If I were seeking factory ammo for an '06 with whitetails in mind, I'd source Remington corelocts on the "cheap" side,or Federal Vital Shok's loaded with NPT's or TSX's on the premium side.

Deer die easy...as a rule of thumb if you are doing your part.

Bullet weightreally is a moot point beyondwhat a particle rifle likes to shoot.