I believe the Sigma is more correctly classified as a double-action pistol. It is hammerless and there is no way to place it into single-action mode. The trigger must be pulled through its full travel to load the striker and fire the pistol.The 9MM Sigma is a no safety, single action, hammerless, glock clone.
I'm confused on this issue. To the best of my knowledge, the Sigma has no hammer or, at least, it is not an exposed hammer. I thought it was striker fired. In any event, a pistol in good working order should not fire though force is applied to the hammer.As stated, the Sigma will not fire unless the hammer is pressed.