It seems to come down to which way it gets interpreted. SA/DA Single action with double strike capability. DA/SA, first shot is DA, all others are SA no double strike. DAO double action only. I have not even gone to a shoot for any of these yet. I want to when I can find a group closer than 60 or 70 miles from me. IDPA, USPSA, IPSC does not matter to me, I just want to find out if I am interested in trying or not.