People often ask me how accidents can be prevented if there aren't such things as loaded chamber indicators and devices that disable the firearms when the magazine is removed. Here is the answer.
Primary Safety Rules
In a tradition which I believe may have been started by Jeff Cooper, most defensive firearms instructors teach some version of the following four rules:
All guns are always loaded.
Probably more people who have been shot unintentionally were shot with "unloaded" firearms than with any other kind.
Don't let the muzzle of the gun cross anything you're not prepared to shoot.
At conventional handgun ranges, if your gun isn't pointed at a person or object, you can't shoot that person or object.
Keep in mind that if the gun is pointed at an upward angle and it discharges, the bullet may travel a very long distance and strike a person or object you may not even see.
Similarly, many walls may not stop bullets, so rounds fired at walls may penetrate and strike a person or object on the other side.
Keep your finger out of the trigger guard, up on the frame of the gun, until the sights are on target and you're prepared to shoot.
Tradition places this rule as rule three; if I were starting fresh, I think I'd make it rule one!
Firearms do not discharge on their own. If, in the heat of battle or in total brain fade, you inadvertently point a firearm at someone you don't intend to shoot, they can't get shot if your finger is not inside the trigger guard.
Most guns are designed to be fired by a finger on a trigger. They are more natural to grasp that way, so the finger tends to drift there under stress. While a single-action pistol would seem more vulnerable to rule three violations, American police officers racked up countless unintended discharges in decades of using double-action revolvers, so it is essential to follow rule three regardless of the type of gun you're handling.
Always be sure of your target and what's beyond it.
The first part of this rule is absolute: you must always identify your target.
The second part of this rule is relative: in a sporting or training environment there is no justification for not knowing what is beyond your target. In a deadly encounter you may be forced to fire in circumstances where you may not even be able to see what is beyond your target. All the more reason to select ammunition which is not likely to exit its original target.
Because we do actually unload firearms, a fifth rule, what my friend and teaching partner, Peter Samish, calls the condition check, is also worth learning:
Whenever you pick up a firearm that has been out of your control, if only for an instant, open the action to determine that it is in the condition (loaded or unloaded) in which you want it to be.
A "click" when you expect a "bang" can be as deadly as a "bang" when you expect a "click."
Are we having a philosophical discussion here, or am I being reprimanded?