All of those calibers are good i shoot a 7mm, .270, 6.5 x .284, .280, and .243. But if i was going to buy a new rifle I would talk a real hard look at the short mags. The short mags will give you better groups and they seem to short a little flatter. This is one of the biggest reason that i like the 6.5 x .284. The short fat case is by far the way to go. I know that you will get alot of good info on here and i dont disagree with any of it this is just my 2 cents. Check your short mags out i dont think you will go wrong with one of them.