pnolans, I think you're starting out on the right foot, but I'll suggest a few things to help you put it in the right place on the path to success.
First off, note the more recoil a rifle has, the harder it is to shoot accurate. Especially with shoulder fired rifles. This was demonstrated not too long ago when the US Army was testing several cartridges for their sniper rifle fired by top ranked competitive marksmen at ranges up to 1500 yards. The .300 Win. Mag. delivered the best overall success in first shot hits as well as accuracy at all ranges. The .338 Lapua faired not to well. But the Army had an ego trip that had to be satisfied so they chose the Lapua.
The same difference exists between the 7mm Rem Mag and the .308 Winchester; the smaller one's going to be a lot easier to shoot accurate at something a long, long ways away. 40% better shooting accuracy will produce more first shot hits than 40% better wind bucking ability.
It's all based on the fact that the more recoil a shoulder fired rifle has while the bullet's going down the barrel, the more the rifle's gonna move off the point it was aimed at when the round fired.
Reloading the .308 Win. case is a lot easier than reloading the 7mm Rem Mag one. New cases in the 7 MAG may well shoot more accurate than traditional reloading techniques used; it's belt causes problems that two sizing dies need be used to correct.
Best accuracy barrel life of a 7 Rem Mag's about 700 rounds with a good match barrel. Maybe 1400 with a factory barrel shooting larger groups. A .308's got at least twice that life.
US Navy Distinguished Marksman Badge 153
Former USA Palma Team Member
NRA High Power Long Range High Master
NRA Smallbore Prone Master