ORIGINAL: SwampCollie
1. Varmints -
First choice = .223 Remington
Second choice = .220 Swift .204 Ruger belongs here
Honorable mention = .22/250 Remington - .222 Rem Mag
Not in this lifetime.
.220 Swift is the fastest factory ammo available cartridge there is that isn't a wildcat, like the Benchrest cartridges.
My great grandpa loved his, and when he and my grandpa were hunting, my great-grandpa shot an antelope from 875 yards away, closer to 900 paces.
He practised with that rifle all the time, and with a gallon of luck, and skill, he killed that antelope, but it was one of those once in a lifetime shots, I wouldn't want to do that, more likely than not, it would be missed completely, since the wind could affect it.
But if I were ever to spend money on an expensive varmit rifle, I would get a .220 Swift, very high velocity and power. The only thing I would classify as close would be the .22-250 Rem, both those cals are what we call "smokers", you see the humidity coming out of the barrel whenever you fire it on a hot, humid, Tennessee summerday.
I really find it strange you didn't bother putting the .22-250 on your list.
Just for the sake of talking trash, the .204 is one of the biggest wastes of brass in firearms history.
No offense.