My ccw class taught updated rules that I think are better:

1: always keep your finger off the trigger until you’re ready to fire.

2: always keep your weapon pointed in a safe direction. (In a defense situation, the bad guy is a safe direction)

3: always treat as loaded until verified otherwise.(Some firearms need to be dry fired to be cleaned)

4: know your target and it’s surroundings. You are responsible for every bullet that leaves your weapon.

(Formatting edit)