Which safety rule aims to prevent unintended injury when handling a weapon?

The safety rule that emphasizes treating every weapon as if it were loaded is fundamental in firearm safety and serves to prevent unintended injuries while handling a weapon. By operating under the assumption that a weapon is loaded, individuals are instinctively more cautious when handling it. This mindset encourages proper handling techniques, such as keeping the muzzle in a safe direction and avoiding unnecessary handling of the trigger. It promotes an underlying discipline that ensures safety at all times, reducing the risk of accidents arising from carelessness or assumptions about the weapon's status.

In this context, the other options contribute to firearm safety, but they are more situational. While keeping your finger straight and off the trigger until ready to fire helps prevent accidental discharges, and keeping the weapon on safe until ready to fire is crucial for immediate handling, these practices are more effective when paired with the foundational principle of treating every weapon as if it were loaded.