i have a nikon m308 on mine it has the bdc set for 168gr projectiles, but baring that i would have got a vortex first focal plane optic, for a lower price you could always try a swfa fixed or variable power
You neglected to mention your price range , so naturally I'd say a hi end Nightforce , Swarvoski, Zeiss or Steiner
but IF your budgets like mine you'll hve to settle for something a little less expensive.
Leupold ,Vortec , Bushnell's Elite series, or SWFA's SS series are all very nice
I like Something in the neighborhood of 4x16x50 , it's a good compromise with more than enough power for long range,
but with a low enough power to give a decent field of view, and be useful offhanded.
Give me a price range you can work with and I'll give you more specifics.