RULE 1: Treat every gun as if it were loaded.
Even if you are picking up a gun out of a case in a store, assume EVERY gun you come across is ready to fire until you personally observe the chamber and see/feel that it is empty. If you set an unloaded weapon down, assume it is loaded again when you next pick it up. The only way to avoid negligent discharges is to make this second nature. IMPORTANT- simply removing the magazine from a pistol does NOT unload it. There may still be a round in the chamber that can kill or injure someone. You must observe the chamber of the weapon to determine if it is unloaded.
RULE 2: Never let the muzzle cover anything you are not willing to destroy.
Do not point even an unloaded weapon at anyone. (The muzzle is the part of the gun where the bullets come out) There is never a reason to point a gun at any person, unless they are a threat to your life, and you intend to defend yourself. You cannot accidentally shoot someone or something if you never pointed a firearm in that direction in the first place.
Rule 3: Keep your finger off the trigger until you are ready to fire.
The natural instinct when picking up a firearm is to put your finger in the trigger guard. DON’T! This could cause an accidental discharge if the gun is loaded. Even if you are at a shooting range with no one around, you should not put your finger on the trigger until your weapon is pointing at a safe target. Almost every accidental shooting could arguably have been avoided by following this one rule alone. This is very important.
Rule 4: Be sure of your target and what is beyond it.
Even if you hear a bump in the night, do not fire at anything unless you know what it is, and what might happen if your bullet misses or goes through your target. Also, be aware that bullets may ricochet off of a hard target and go in unexpected directions- sometimes back at you. Ensure that what you are shooting at can handle being shot, and that you are not going to injure anyone unless they are an actual threat. Do not use telescopic sights as a substitute for binoculars when identifying persons, animals or objects.
Notes: Learn these rules until you can recite them without looking. There is much debate over the exact wording, but the point remains the same. There is no excuse for unsafe firearm handling. Discipline yourself to follow these rules and avoid becoming a statistic. If you do not know how to do these things (eg. you are not sure how to safely inspect a weapon to ensure that it is unloaded), find someone who can show you before you attempt to learn on your own. Always read the manual that is provided with your weapon. Each weapon is different, and has unique facts that must be known about it to ensure its safe operation.