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  • Writer's pictureBrad Parker

The 21-Foot Rule: More Like a Guideline


Police body camera photo of man armed with knife aggressively advancing towards an officer.
The 21-foot rule is often cited in self-defense training.

Profound thinking here regarding a concept that most firearms instructors and self-defense instructors have advocated for decades.


It's called "The 21-foot Rule" and generally it is defined by the amount of distance that an attacker can cover before a person can react and effectively defend themselves. It's attributed to law-enforcement instructor Dennis Tueller from Utah and has been part and parcel of training in many, many departments.


"The drill itself placed an assailant, armed with a knife, 21 feet away from a police officer. The bad guy then charged the officer and through enough trial an error it was discovered that an average officer could draw and fire two rounds when the bad guy started running at that distance."

I have excerpts from an old training video which shows legendary martial artist Dan Inosanto role- playing an attacker in police training videos. It's horrifying to see him suddenly draw a training knife and attack police officers involved in the training.


This "rule" has apparently started to approach a real rule, legally speaking. Self-defense attorney Tom Grieve tells us how this has started to happen in the video below. He points out the very real problems the 21-foot rule can present for self-defense. Take a look.




Some of the highlights of his presentation:


  • Legal arguments are being made with this 21-foot rule as the defining aspect rather than the totality of the circumstances.

  • The important part about this concept is less about the distance of 21 feet and more about the realization that there is a reactionary gap when defending yourself.

  • We need to remember that this particular rule resulted from training on a firearms range, during the day, with a previously identified attacker, using trained police officers reacting from an open carry holster. In other words your mileage may vary and most likely it will vary by being even an increased reactionary gap.

  • Most police officers and concealed carriers will face an even more complicated situation which entails an even LARGER reactionary gap than 21 feet because:

  1. Drawing from concealment takes longer and is more complicated than an open carry;

  2. Citizens are more hesitant to draw their firearm because, in many jurisdictions, displaying our firearm in situations that are not deadly force scenarios can result in criminal charges against us.

  3. Committed attackers can continue their homicidal actions after being shot for far longer than the 1.5 seconds used in the 21-foot rule. Grieve cites FBI and DOJ studies which suggest attackers can continue for between 10 to 15 seconds even after being mortally wounded.

  4. Some studies show that up to 85% of officer involved shootings happen in low light situations which hamper the effectiveness of identifying the threat and then effectively dealing with the attacker. Citizens could be less effective than police officers if it's presumed cops get more training than civilians. (In many cases, this is not always the reality. Some citizens have a higher level of training as well as a higher level of skill).

  • The threat from an edged weapon -- even the lowly folding pocket knife or a box cutter -- not be underestimated. A study from the UK shows that a significant number of fatalities result from just one single stab or one single slash.

  • We, as responsibly armed Americans, cannot be bound by a "rule" that establishes a definitive line that must be crossed before we can respond. In the case Grieve cites, the attacker was able to advance 37 feet before being stopped by two police officers, both firing repeatedly at an attacker, from full-sized duty weapons.

As a final warning -- below is a result of the testing of the 21-foot drill linked to above:


Of the 57 officers who participated in this drill, 7 were not able to draw their firearm successfully. For those that actually got their shot off, the average time it took to draw and shoot was 1.43 seconds. The fastest officers shot in .93 sec and the slowest was 2.4 seconds. These officers hit their target 76% of the time. This means only 66% of officers were successful in hitting a target running at them from 21 feet.


The way is in training.


Train like your life depends on it.


Sources cited:


Buchanon v. City of San Jose, (9th Cir. 2019) hyperlinked with this URL https://law.justia.com/cases/federal/...

(F. Borelli, “Twenty-one Feet Is Way Too Close,” Law Enforcement Trainer, July/August, 2001, 12-15.)

(William Murphy, “Shooting Straight in the Dark,” Police Magazine, June 2, 2009.)

(E. Webb, J.P. Wyatt, J. Henry, and A. Busuttil, “A Comparison of Fatal with Nonfatal Knife Injuries in Edinburgh,” Forensic Science International, 99 (1999), 179-187.)



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