You will be cocking the hammer on a gun that is loaded!!!
Well, you think it is not loaded since you are trying to load it, but "All
guns are loaded when you pick them up, until you check to see that they are not."
So I do not recommend that method. Although having a pistol with a firing pin block will help reduce the chances of getting a loud and unexpected sound.
Notice how I skated around the argument of accidental discharge versus negligent discharge?