Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. A gun is a muzzle or breech-loaded projectile-firing weapon. Many definitions for gun exist depending on the nation and branch of service. In the past, land-based artillery tubes were called cannon while sea-based naval cannon were called guns. The term gun evolved into a generic term for any tube-launched projectile-firing weapon used by sailors, including boarding parties and marines. Firearms are also often synonymously termed as guns, shotguns or handguns... Learn more about guns, firearms, laws and politics concerning guns with the help of this book.