The Dangers of the 21-Foot Rule

By Dave Dolbee published on in Concealed Carry, General, Safety and Training

The word “rule” has been carelessly tossed about by law enforcement and CCW trainers for decades—perhaps it was just misunderstood. In truth, when talking about the 21-foot rule, most are referring to the “Tueller Drill.” Careless lips have led to some dangerous conclusions, especially among the civilian population. It’s a confusion that’s being cynically exploited to get headlines, and it has even reared its ugly head in the courtroom a time or two, but it needs to be addressed for safety.

Police Officer aiming a Glock pistol with a red barn in the background

Teuller’s drill is well suited to law enforcement and civilians, but the 21-Foot Rule is not.

What Is the 21-Foot Rule?

My first introduction to this topic came about 25 years ago while attending the sheriff’s academy. I remember the class and, more important, the video “Surviving Edged Weapons.” The video and instructional seminars were based on research by Salt Lake City trainer Dennis Tueller. The “21-Foot Rule” was a measure of distance that related to the time it would take an officer to recognize a threat, draw a sidearm, and fire two rounds center mass against an attacker charging with a knife or other stabbing weapon.

To be clear, this article is not intended to be the rule or guide to law enforcement. In fact, most of what this article covers will be common knowledge to today’s LEOs. However, I would hope those with experience behind the badge will chime in and challenge or correct the assertions I scribe here by supplementing it with their own experiences. The ultimate purpose is to give some real-world guidance to the nonprofessional concealed gun handlers reading The Shooter’s Log.


The first issue I have with the 21-Foot Rule is the belief that it is somehow rooted in police doctrine or a legal standard. Removing the number “21” and the word “rule” would go a long way toward dispelling the myth. Tueller’s research did not culminate in a rule; you are not suddenly safer at 22 feet than you were at 20. It is important to distinguish that Tueller developed a drill, not a standard.

Shooter behind cover

Movement and the use of cover is your best defense against any attacker. The is doubly true of an attacker with an edged weapon.

Just as many firearm enthusiasts insist the distinction between a modern sporting rifle and an assault rifle, magazine versus a clip, and a dozen other examples we could come up with off the top of our heads. I believe we need to properly identify our subject as the Tueller Drill and not the 21-Foot Rule. This is not only factually true, it goes a long way toward setting the correct mindset of the neophyte gun handler.

There were two main conclusions that can be contributed to Tueller’s research. First, an attacker with a knife could cover 21 feet in about 1.5 seconds. (This is not word for word, but it covers the general gist.) Second, a helluva lot of law enforcement would be lucky to recognize a threat, unholster their sidearm, and successfully stop the threat from being able to deliver a blow with a knife in less than 1.5 seconds. This was quite a revelation at the time and created much discussion.


Tueller’s lesson should not indicate that anyone, even if they have a knife in hand, is a justified bullet sponge. How many of us carry a pocketknife? Every waitress or busboy in a restaurant would have a target on their chest. Not even in the context of a heated confrontation could you immediately jump to this conclusion. The lesson does not teach that we should shoot a hostile actor with a knife if they are within 21 feet. The lesson merely put a number to the test data and created a mindset for officers to rethink their response and posture to a threat or potentially sudden dynamic attack.

The mindset was fine, but the lessons that followed…not so much. Tueller’s research revealed training deficiencies of the day. As previously stated, it created a lot of discussion, which was good. Where it went wrong, in my opinion, was when they started teaching the number over the mindset. I recall this being demonstrated on the range at the academy. A large, intimidating deputy with a rubber knife rushed a student from 21 feet. The deputy did not run, just marched at a quick pace wielding the knife over his head and screaming obscenities.

Bob Campbell shooting a 1911 pistol from a retention position

Seldom in an emergency situation where you have to draw and fire quickly will you ever see the gun’s sights.

The student had to recognize the threat’s approach, unsnap his holster, and draw his weapon. He failed. In fact, the truth be told, we all failed. Some may have cleared leather and pulled the trigger, but the threat was so close he still would have struck a blow falling on you. Let’s not forget the audience here. You are likely carrying concealed, not openly in a Sam Brown.

The 21-Foot Lesson was—graphically—received. Unfortunately, at the time, we learned the number more than the correct lesson. In time, however, we learned to get off the “X” instead of being a static target. Instead of backing up in a straight line, we were taught to react by moving “off-line.” (Attackers in these scenarios may be so enraged they continue on the beeline path instead of tracking you.) More important, we were taught to read body language, situational awareness (which directions could you move off-line, soft and hard cover, etc.), reactionary gaps, and other close-quarters defensive techniques not involving a firearm.

Final Thoughts

The focus of The Shooter’s Log does not include training civilians to be cops or instruction in matters of law enforcement. However, I see far too many videos of self-professed firearm trainers, tactical weapons specialists, home defense “experts,” and even a few prior LEOs who teach like they did to officers or cadets at the academy or in the military and not to civilians. Sadly, I would say while I respect the effort, they have no business standing in front of a student. Too often, I have heard friends (after such training, watching a cop show on TV, or reading something on the Internet) throw out the term “21-Foot Rule”  and improperly state it as a threshold of safe versus justifiable homicide.

I hope, after reading this and the comments from readers with much more knowledge and experience than I have, that you dedicate some of your concealed carry training to going beyond the minimum gun-handling skills and—as important—practicing your communication skills, situational awareness, and good old-fashioned common sense.

What is your impression of the 21-Foot Rule? Have you ever heard of the Tueller Drill? Have you practiced it? Share your answers, opinions, or experiences in the comment section.


Growing up in Pennsylvania’s game-rich Allegany region, Dave Dolbee was introduced to whitetail hunting at a young age. At age 19 he bought his first bow while serving in the U.S. Navy, and began bowhunting after returning from Operation Desert Shield/Desert Storm. Dave was a sponsored Pro Staff Shooter for several top archery companies during the 1990s and an Olympic hopeful holding up to 16 archery records at one point. During Dave’s writing career, he has written for several smaller publications as well as many major content providers such as Guns & Ammo, Shooting Times, Outdoor Life, Petersen’s Hunting, Rifle Shooter, Petersen’s Bowhunting, Bowhunter, Game & Fish magazines, Handguns, F.O.P Fraternal Order of Police, Archery Business, SHOT Business,, and others. Dave is currently a staff writer for Cheaper Than Dirt!

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Comments (77)

  • Frank Z


    I try to stay home as much as possible.


  • Wagonmaster


    The late Louis Awerbuck had a great way of teaching the lessons of the Tueller Drill. It was conducted in three stages with inert training weapons (blue gun and rubber knife). A class volunteer made three different “attacks” on Louis from 21-feet. The first: Louis had his back turned and the attacker launched and Louis responded (drew and presented while standing on “X”) upon an oral signal from the timekeeper. The drill ended when Louis yelled “Bang!” In this first drill, he got off a simulated defensive shot when the attacker had covered about half the distance–then again, both started on the same signal.

    Drill 2 was set up identically, except the attacker launched whenever he wanted–no oral warning, and thus more like real life. Typically, the “Bang” came when the attacker was almost within an arm’s length of the defender, who could react only when he became aware that a sneak attack was underway.

    Drill 3 was setup and started identically to Drill 2, but as Louis turned, drew and presented, he moved 90-degrees off-line and even fish-hooked back slightly in the direction of the attack. The attacker tried to follow him, but the defender now had the initiative and the “Bang” always came when the attacker (a young, fit guy) was no closer than 6 to 10 feet.

    The takeaway for students was to begin to move off-line as soon as Condition Red kicks-in. I believe the FBI changed its training protocol around 2011 or 2013 to begin emphasizing quick hits from presentation at 3 yards–a more realistic handgun combat distance–as well as practice for 7 yards and further.


  • Steven Silva


    Very interesting reading…This all boils down to training, whether it’s 15-20-30-feet you need to know how to draw, when to draw and who to draw on and fire …….you get these const, carry fanatic’s that think just strap on a gun and your dirty harry…these are the guys that get killed or other people killed…no training, at least a cc class will help some, most people have never really fired a gun, do I believe in 2nd admed..yes, but there should be some kind of training first…….sorry for getting off the line, My problem is finding someplace to run drills…I run drygun drills at home but it is hard to find somewhere to live fire…


  • Bob Moody


    I recall the 21 foot rule being bandied are even before 25 years ago. You really hit the nail on the head with this article. I began my law enforcement career in 1957 (retired in 2000) and have seen many demonstrations of attacks with blades and am aware of at least one case where it was demonstrated in court on a civil suit against a Leo. I guess the thing that has disgusted me the most in my 60 years of law enforcement affiliation is the number of experts out there who have never spent a day on the street. Oh well that will never change and it’s actually getting worse with the social media’s influence. By the way, I still hit the range at least once a month.


  • Longshor


    Sorry, but as an addendum to my last comment, I say this. NEVER BE A STATIC TARGET. As your assailant moves, so should you. Even at 15 feet, a side step or so should garner the 3 seconds you need to draw and put them down. Its the old “knife to a gunfight” RULE. The RULE clearly states, the one with the gun wins.


  • Taz


    Just to update everyone on this 21′ Rule/Guide that you need to put yourself between you and the bad guy, it has been recently updated and proven, that you now need approximately 30′ of distance to draw your weapon and fire a round before the bad guy can make contact with you with a knife in his hand. It is also good practice to not just stand in one place but to move side to side as it will disrupt your attackers advancement towards you as he has to change direction an attempt to get to you.


  • Bob Cox


    As a former LEO and firearms training officer, I could not agree more with Dave’s comments. I spent a lot of time trying to explain this concept to LEOs that had received training at academies and elsewhere. Focusing on the numbers often gives the wrong impression, and calling something a rule leaves the typical entry-level police officer with the impression that he must always wait until his attacker is within that 21 feet. Good job Dave.


    • Dave Dolbee


      Thank you Bob! ~Dave Dolbee


  • Tom Morse


    Reading this makes me realize I need a lot more training. I have a cc permit but not the knowledge to go with it.


    • Longshot


      Well Tom, the fact that you realize you need more training, is in fact your first lesson. Good for you!!! So many, because of peer pressure or machismo, refuse to believe that they dont know everything about their weapon.
      Here’s lesson #2;
      Dont rely on the interweb. Your best teacher is a military veteran, or an active LEO. We have lived it, and have insights not taught in any, or at least most conventional courses.
      Good luck.
      Class dismissed.


    • Randy


      Tom, when you find someone who can’t benefit from more training, it will be because they are dead. I’ve been carrying for over 30 years and I still train, take classes, watch DVDs, practice dry firing, read books and spend time at the range. There are a lot of good sources out there, but as with everything decide for yourself what will work best for you. Then hope that you are ready if it is required and pray it is never required. Never stop learning.


  • George


    Well… I thought the issue was the bad guy had to be at least 25′ from your gun or you could not prove imminent danger in a court of law if sued or charged with a crime.


  • Cea


    To me, it is the same as calling a magazine a clip. I don’t care what you call it, I still know what is meant. The “Tueller Drill” shows that the average person can cover/run 21′ in 1.5 seconds. And, it usually takes a bit longer for the average (minimally trained shooter) to draw and fire a round in self defense. If the runner has a weapon, the other person may already be behind the curve.
    21′ rule, Tueller Drill, one in the same to me. What’s the big deal here?


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