I'm sure most everyone is familiar with Alec Baldwin shooting two people on a film set and immediately claiming to be the victim after initially seemingly accepting responsibility that he was the one who fired the gun.

Well now he's walking that back by claiming he never pulled the trigger, rather he "pulled the hammer of the gun back as far it would go and then released it" and when he released it the gun went off all by itself apparently.

Okay so I'm not that familiar with guns, especially guns that would have been used in the 1800's. Can someone more knowledgeable help me understand what distinction he is trying to make here?

Wouldn't pulling the hammer back and releasing it pretty much be the same thing as pulling the trigger? Is he trying to make this distinction to try and fool people into thinking he didn't really fire the gun and it somehow went off by itself? Or is what he's claiming legit and pulling the hammer back and releasing it wouldn't cause the gun to go off under normal circumstances?