what does single action or double action mean in a semi automatic handgun?

Question

i know in a revolver single action means you have to pull the hammer back and double action means you can just pull the trigger and it will cock and release the hammer all in the trigger pull. i'm just wondering how that applies to semi auto handguns.

Answer 1

DA means that the full pull of the trigger will pull the hammer back and release it

SA means that the hammer is or needs to be back before the trigger is pulled.

Answer 2

In double action mode, your weapon does two things upon pulling the trigger. The first part of the trigger pull cocks the hammer. The second part of the trigger pull actually releases the hammer causing the gun to fire - as you stated. Basically, with semi-autos, some are double-action-only and some are double action on the first shot and single action on each subsequent shot. Double-action only semi-autos reset to a full and longer trigger pull after each shot. The cool thing about semi-auto pistols that go into single-action mode after the first shot is that it becomes easier to land follow-up shots in single action mode due to the light trigger pull. It's a nice feature...especially in a ccw situation where you're reacting to a crisis and your nerves are twitching. Every advantage helps.

Answer 3

The recoil/ cycling of the previous round cocks the hammer...then just pull the trigger again.