Hi Keith,
The 300WM won't have half the barrel life of the 6.5*47. Someone has told you some porkies there. If you want to confirm this there is a barrel life calculator somewhere on accurateshooter (hopefully someone will post a link here). You will use twice as much powder, projectiles and brass are way more expensive and you will get half the barrel life. All in all I would say it will cost you more than twice the $.00 per round to run.
Many have tried in F class based on ballistics and 1000 yard BR results but nearly all have faded away. It is however a popular cartridge in Long Range Benchrest where you can either use a very heavy platform or a muzzle brake in the lighter class (although not as popular there)
In a bipod F class outfit the 6.5*47 will simply run rings around the larger caliber as far as consistent accuracy goes for all but 0.1% of the shooting population. It has little felt recoil and will hold and track beautifully. It would be my pick of the above two for what you want to do. Is there much large game down there that would require a cannon?
If you get the 6.5*47 (308 bolt head) heavy barrel in a bipod outfit you may be tempted to get a lighter 308 barrel down the track and try FTR (bipod only competition). OR if you want to up the ballistics you can go to a 284, 284 improved, 280 AI, 30-06AI, 30-284. All these calibres are very competitive in F open and remember this
ACCURATE RIFLES ARE FUN RIFLES
- you will have a ball if you are hitting around the middle but be frustrated to hell if you aren't and it is belting the hell out of you at the same time.