hold on look at how you LOAD the hand cannon it is a single charged round so these are not regular hand cannons that load individual rounds that require standard Hammer and pin to hit the cap on a single round. Your thinking current world technology which is the distant past in Destiny. I took hand cannons as tech meets wild west. So the principle of a hand cannon is there but the technology in the weapon is all electronic so the ignition and firing mechanism is contained within the large drum you insert into the revolver. The Hammer action is purely for aesthetics nothing more. What doesnt make sense is the ballistics for weapons that fire an actual round dont suffer from drag or cross winds or even gravity. Also the fact that gravity per planet and moon doesnt vary so a jump on Mars is the same as a Jump on the moon.