Revolvers are easy: DAO = Double Action Only SAO = Single Action Only DA/SA = both Our standard military pistols still fit the revolver definitions: M1911 = SAO M9 = DA/SA Some newer automatic pistols still meet the old definitions too: Taurus 24/7 also meets the DAO definition Taurus 845 meets the DA/SA definition XD/XDm meets the SAO definition What doesn't work is the pre-set hammers and strikers. The ruger LCP is a pre-set hammer and the Glock is a pre-set striker. They are not DA, nor SA nor DA/SA. If you have a misfire on the pre-set trigger, they are not DA to just fully recock again. What do you like better for a new acronym these pre-set strikers and pre-set hammers?