Here in the NE USA it's mostly woodchucks and the occasional fox or crow and ranges are usually under 250 yards, so my .222 Rem. and .223 Rem. single shots are pretty useful. I use the 50-grain Hornady SX in both of those, with either IMR 3031 or H322 powder.
Sometimes, as with baited coyotes over a frozen lake, a little extra is provided by an elderly Rem. 700 ADL in 6mm Remington, using 85-grain Sierra spitzers and IMR 4350. Effective range with this unit is extended to 400 yards or a bit more.
All three of these guns will shoot into a half-minute, within their effective ranges.
I don't think I've ever fired a factory load at a varmint. Experience goes back to 1964.