Listed here are the four cardinal rules of Firearms Safety. Also included are the additional four rules of Firearms Etiquette (for those of you who handle or want to handle a lot of firearms)

The Four Cardinal Rules of Firearms Safety


All Guns Are LOADED


Point the muzzle in a safe direction (Safe meaning "at something you are either willing to destroy OR at something that can effectively stop the round)


Keep your finger straight along the frame until you are on target and ready to fire


Be sure of your target and what's behind it

The Four Rules of Professional Firearms Etiquette


Don't accept OR hand a weapon to anyone unless the action is open


Don't lay a weapon anywhere unless the action is open


Don't let the muzzle of any weapon that you handle (or anyone else) cross anyone's body


Whenever you handle a weapon that has been out of your control, verify the condition of the weapon immediately

These rules are taken from the Instructor's Book of the
Arizona Basic Police Firearms Instructor Course.  Thanks to Arizona
Police Officer Standards and Training (AzPOST)and the Maricopa
County Sheriff's Office for providing me with the training and
the manuals/materials.