Hello and welcome to LRH.com!
I think AJ hit the nail on the head w/ his comments.
Lets face it... if you are just getting into lrh than you need to brush up quite a bit on your target shooting skills which equals possibly thousands of rounds of target practice in the next couple years. A wsm or even a win mag is going to get pretty espensive to shoot target with considering ammo alone. The 308 will offer lots of match grade factory ammo, lots of el'cheapo rounds for plinking and you will have a barrel that will last you until you become proficient at shooting.
If you were to buy a 270 wsm, the biggest thing you will "gain" is that when you are just starting to feel comfortable shooting that rifle at long range, you will then get a new barrel because your original barrel will be totally shot out!
The two best rounds for someone to learn the basics of long range shooting and doesn't handload are the 223 rem and the 308 win BAR NONE! easy on barrels, inexpensive ammo, and long long barrel life. Not to mention that you can find ammo at almost any mom and pop gas station in the country if you happen to run out on a hunting trip.
Once you get into it and get used to shooting and want to extend your range... then start looking at the bigger magnums.
A compramise in getting better balistics and not so expensive ammo would be something like the 7-08 or the 260 rem. Problem is that they are much harder to find ammo for.
IMHO you'll do fine learning to shoot w/ a good old 308 win. Forces you to learn wind and tradjectories but is known to be a good efficient cartridge. There's a reason that the US military still uses the 308 win for their primary sniper rifles. It's by far not the best long range round, but it works.
Britz,
You make some good points, but... I dont think it's necessary to shoot thousands of rounds to become proficient for LRH. The marksmanship is basic marksmanship, whether 100 yds or a 1000 yds. Now there are some complications when you reach out there, like wind doping, making sure sure your rifle/sightline is plumb, etc. But a guy who can shoot a .25 MOA group with a good rifle and load @ 100 yds should be able to shoot an MOA group @ 1000 yds with minimal practice.
So having said that, most rounds down the tube will usually be fired in load development and trajectory/BC validation. Depending on how many differnt loads one tries, this should be able to be accomplished in a few hundred rounds. If one gets his load development done in 300 rounds and shoots another 100 rounds a year, that barrel should last maybe 10 years at wich time he is ready for a sweet hand lapped custom barrel. And if you want longer barrel life, go to the 300 WSM which will rival the 308.
A 308 is a great cal, but the 270 WSM has a lot better ballistics including 20% less wind drift. I guess we all have our preferences.
As for cost of shooting, 308 factory ammo will be a little cheaper, but the 270 WSM has a good selection of relatively cheap stuff and good stuff. And if you are talking about shooting thousands of rounds of ammo (hope you are reading this Slafav). You could buy the handloading eqipment and components after you have shot 2000-3000 factory rounds for same. Also, I think we both know that factory loads will differ from lot to lot. So every time you go to Wal Mart and get your ammo, you are back to shooting a few sighters to see where you are. And if you run out ammo while you are hunting, that is PPP and you may not get the load at the mom and pop country store that you got back at Wal Mart and even if you did, it would be a different lot. Besides, in all the stores around here, there is almost as good a selection of 270 WSM as there is 308.
My philosophy is... if you're going to go LR, then go... Get the rifle that is capable and do it. If you want a plinker then get that later.
Being ex-military, I have to agree with you that there is always a reason that the military does something, and from my experience on being in the decision making process a few times, it aint always a good reason
, not to say that the 308 wasn't a good cal, but neither did they have the WSM cartridges at the time.
Best,
-MR