I have found one of the more confusion aspects of guns is what defines the trigger action, and I confused this a lot at first but now feel I have a good understanding of what makes a gun Single Action Only, Double Action Only or Single and Double Action. Your best bet is to watch my attached Vimeo video as it not only describes trigger actions but also has the added benefit of the visual examples of each type of trigger action. Read full article here: https://www.replicaairguns.com/2011/11/2/trigger-action-explained-sao-dao-single-double-action.html