To add some more, there is an additional safety on most modern pistols, the firing pin block, sometimes referred to as a drop safety. Its purpose is to prevent the firing pin from contacting a cartridge unless the trigger is actually pulled. So, in theory, you could conceivably drop a pistol so equipped directly on a cocked hammer, and it still wouldn't discharge. Or to put it another way, even if the safety notch on the hammer broke as you were decocking the pistol, it still wouldn't fire, PROVIDED you didn't have your finger on the trigger. Decockers used to give me the willies, then I did some research and realized it's only part of a safety system. Now, it's my preferred system, I got rid of everything that wasn't DA/SA with decocker. Only "down side" to decockers is the initial DA to SA transition, but that's what training and practice are for. Later.