McCree's primary fire will fire two shots per second from his revolver. Each shot does maximum 70 damage for a bodyshot, as the hitscan bullet has a falloff range from 20 to 45 meters. It also has no spread and is able to inflict a headshot.
His secondary fire will fire all remaining rounds, with the rate of firing all 6 rounds in ~0.67 seconds, with each shot dealing 27.5-50 damage up to a maximum of 300 total damage. This method has a wide spread and cannot deal headshots. Fan the Hammer can be cancelled early by using any of McCree's abilities (including Deadeye).