I have a 221 Fireball in a CZ 527. I love the cartridge and the gun. Just about the perfect combination. I have had a 220 Swift, 22-250, .243 Win, several .223's and a .204 Ruger. I didn't dislike any of them but I would never part with the Fireball. Mine loves a 40 grain VMax with 16 grains of Lil Gun powder. Accuracy is awesome and it also gives top velocity at 3565 fps.