My prefered one is Rem 700 using 223 ammo, but in general it depends on distance and your accuracy. You can use anything from .17 to 6 creed and it's all going to work, but might need some more accuracy with lower cals. My go to is Federal, but I've heard Fiocchi makes pretty good 223 ammo
https://gritrsports.com/shooting/amm...ammo/223-ammo/ , got few boxes of Fiocchi, Hornady and Double tap(never tried those) from this store, gonna test which one my rifle prefers