The smallest gun in the world is the Swiss Minigun; manufactured in well… Switzerland. It measures in at 5.5 centimeters and fires at 121 meters per second with a 2.34 millimeter caliber bullet. It weighs about 19 grams; the size of a slice of deli ham. It can kill a person at close range, but so can a BB gun: metal in chest or head = bad and painful. It has a big fan base in the Middle and Far East, and is illegal to own or import to the United States or the United Kingdom; ironically, it is legal in Canada. It is a double action revolver and performs all the functions of its full sized counterparts.
It retails for over $5000 USD for the stainless steel model and lots and lots more for the customizable, solid gold model. Adding diamonds is optional and those babies sell for around $30,000 USD.
It has been confirmed by the Guinness Book of World Records as the world’s smallest revolver.