If I were to go out to buy a long range varmint rifle today, I think I would get one in 220 Swift. There aren't many rifles made in that caliber, however, so gun selction is limited. I know Remington makes one, but I'm not sure who else.

If you do get a Remington, the trigger pull will be set way to heavy, but the trigger is easy to adjust. If you aren't comfortable adjusting it yourself, most gunsmiths will do it at a fairly reasonable cost.