Re: Good long range varmint caliber?
If you can find an 8 twist .243 you are golden. But in factory guns, I'm not aware of one (I've looked). The best I can find is a 9.25 which depending on your altitude should shoot up to 100gr flat bases and possibly 105-107gr BTs. 90's on down for sure and way out there.. past 1000yds.
The SA 6.5's (.260, 6.5 Creed, 6.5x47) can sling them too and most of these have good factory twists (8) to shoot anything from 107s to 142s. Little more kick but more downrange energy. These will outshoot the .243 at max distance.
I'd keep it simple as there are many components for these available (usually when there isn't a complete depletion of everything).
If you don't reload, .243 or 6.5 creed.. if you do, any.