So my fiance just purchased me an M700 SPS Varmint LH chambered for .308 win for Christmas. I already have a Bobby Hart Long range target laminate stock from stocky's on order along with an EGW 20moa 1-piece base, and Rifle Basix Trigger. In 10 days when i can pick the rifle up (CA sucks) all of it will be dropped off at my smiths to be bedded and installed. My question is this: As this gun will be used purely as a trainer for long range shooting, what will best the be combination of high BC bullets and what powder to get me the longest supersonic range out of the .308. It is a 12 twist 26" bbl. My 4x16x44 Nikon monarch will get transplanted to this rifle from my .300 ultra until the Viper PST are released then both rifles will get one. Thanks!