The 175's should do just fine in a 1:12 twist. 155 Scener would be another place to try, or the Hornady A-Max. Buy some Varget and experiment putting some loads together.
600 yards is pretty easy shooting. Most people on here have made some very good points; calibers able to run better BCs at the same or higher velocities will still be impacted by the wind, no doubt about it. A .300WM will have less wind drift... But I think the thing to ask yourself right now is, is it worth it? The .308 may be harder to shoot in the wind than the 6.5's and what not as well as the .300WM and 7RM, but all of those cost more to shoot, you will have a more difficult time finding match quality ammunition in the store, and you'll have to get set-up for reloading whatever other caliber you get... in addition to the new rifle.
I'm going to say, stick with what you have for now and use it to learn reading the wind better. Once you've improved your ability to shoot with wind, perhaps you will be happy with what you're running. It doesn't sound like you're doing any competitions of any sort, I doubt you're hunting out to 600 yards; I don't see where you NEED the advantages that come with those other calibers considering the cost involved. Punching paper just for your own enjoyment is great, but if you already have a good rifle but have trouble in the wind... the answer isn't another good rifle, it's improving the shooter.
Anyway, that's just my logic on this.
