RE: 300+ yard Rifle which one?
If this gun is just going to be a beanfield rifle or something of that sort where a lot of walking isnt involved, I would opt for a Remington Sendero SF in 300 Win Mag. This gun has an HS Precision synthetic stock and a nice fluted barrel, and it weighs in at 8 1/2lbs I believe (havent looked at one in awile) You're definitely on the right track for the scope, I love my Nikon, very bright scope.
Best of luck,
timba