Nolacopusmc
*Banned*
Not making fun of you, but this is a perfect example of the kind of information that would be covered in a quality CHP class, and yet people still think it is not necessary.
To answer your question...verybriefly and basicly.
SA/DA refers to the action that is performed when the trigger is pulled.
1. 1911's and old cowboy revolvers are single action. The hammer must be manually cocked and the pulling of the trigger performs a single action--releasing the hammer.
This is a relatively "light" trigger pull
2. Double action are things like the typical revolver and DA semi's, where pulling the trigger cocks the hammer and releases the hammer...IE..double action- two actions.
This is a relatively heavier trigger pull
3. Striker fired actions (constant actions) like Glock, Springfield XD, etc...are a little different in that they are very basically a firing pin on a spring. I am sure there is someone here that can articulate striker fired actions than I can.
This is a constant relatively medium trigger pull
4. Most semi's that are not 1911 style, the first shot is double action, and every shot after that is single action, resulting in a firearm with two distinctly different trigger pulls. This is what you will see with most LEO and MIL type firearms other than Glocks. SOme consider this a "safety" mechanism from unintentional discharges since it takes much more force to fire the first shot.
