The "21-Foot" Rule

Another factor to consider in a potential self-defense situation relates to the “21-Foot Rule.” This “rule” was developed as a guideline from research conducted by Dennis Tueller, a Salt Lake City police department instructor. According to his research, a person charging toward you with a knife or other sharp-edged instrument can travel 21 feet in the time it would take you to recognize that there is a threat, draw your firearm, and fire two shots.

It’s important for you to also note the following.

• You should not immediately draw your firearm when someone is approaching you because that other person could be coming toward you without planning to harm you. Staying aware of your surroundings while also thinking about why someone might be approaching you and looking to see if there are innocent bystanders in the area should help you react in an appropriate and timely manner.
• The 21-Foot Rule is only a guideline to help you understand the reactionary gap you could face if you are attacked unexpectedly. This guideline does not provide you with an absolute defense. In fact, if you should shoot someone, you must be prepared to fully justify your actions, including why the situation was life-threatening and why your reaction could not be delayed.

The following series of illustrations demonstrates the reactionary gap that you could experience during an unexpected attack. Notice how close the "attacker" is before the shooter has his gun fully drawn and is ready to fire.