There are two 24/7's, the first 24/7 was a double action only, and the second model, the 24/7 Pro is double and single action, you will always fire in single action because when you rack the slide to chamber a round, it cocks the hammer back and then you fire. Since there is not a decocker on the 24/7 then the only way it will switch to double action is if the round missfires, then you can pull the trigger again and with any luck it will shoot...