This article first appeared in the Network's May 2008 journal.

by Gila Hayes

25 years ago, an officer with the Salt Lake City Police Department by the name of Dennis Tueller wrote an article entitled “How Close is Too Close,” which initiated considerable discussion about law enforcement officers’ defensive options when confronted with a suspect armed with a contact weapon. Tueller’s study is now one of the classic survival lessons, taught to students of armed defense, both in police circles and by trainers educating qualified armed citizens, as well.

For readers unfamiliar with the name, Dennis Tueller retired with the rank of Lieutenant from the Salt Lake City, UT Police Department, taught at Thunder Ranch and International Training Consultants, the American Pistol Institute (Gunsite), Defense Training International, American Small Arms Academy, the U.S. Dept. of Energy’s training center, International Association of Law Enforcement Firearms Instructors and more. Currently he is with Glock Professional, Inc. as a firearms instructor teaching that company’s police firearms instructor and armorer courses.

Dennis Tueller’s study went so far beyond him that his name has become inextricably linked with what is erroneously called the “21-Foot Rule,” as if an arbitrary distance could be established beyond which an assailant armed with a contact weapon was no longer an immediate threat, or put conversely, justifying use of deadly force if an assailant with a contact weapon was within a certain distance. (To read the original article, visit

In the year that marks the 25-year anniversary of Tueller’s original article, I thought it would be interesting to ask Dennis Tueller to revisit the topic, and see how his thoughts have changed over time.

EJournal: Dennis, 25 years ago you wrote an article sharing some conclusions drawn from a simple test you devised. Would you tell us about the history of what we have come to call the Tueller Drill?

Tueller: At the time, I was assigned to the Salt Lake City Police Academy, conducting firearms and other use-of-force training. I was also teaching part time at Gunsite. During an academy training session, we had been doing draw-and-fire drills at the seven-yard line. During a break, we were discussing use of force issues and one of the recruit officers asked what to do if someone was attacking you with a knife, a club, or some kind of a contact weapon. He wanted to know how close an attacker should be allowed to encroach before the use of deadly force was justified to stop him.

At first, I thought about saying three or four steps, but then I realized that I didn’t have any idea how close was too close. I thought, “We can do better that this!” Since we already knew the average time it takes to draw, fire, and hit a target at seven yards – which was about 1 1/2 seconds from the holster – I decided to see just how long it would take someone to cover that same distance.

So we had one recruit officer play the role of the “bad guy” and another played the role of the “startled officer.” We put them 21 feet apart, and when the bad guy role player decided to start his attack, we started the stopwatch, and when the bad guy made contact with the good guy, we stopped the watch. I was quite stunned to discover that the time was roughly 1 1/2 seconds!

Then we tried the same exercise with everyone available in the class – some younger, some older, big and small, male and female – and all of them could run that seven yard distance in about 1 1/2 seconds. Of course, this was before Simunitions® or Airsoft®, but later we did test it with dart pistols. What we found was that if you’re ready and if everything goes perfectly, you might get the gun out and get a shot off before the bad guy role player makes contact. That is not good enough! Shooting does not stop the action.

So we started considering other things: seeing the danger so you had an early warning, getting the gun out, issuing a challenge, getting off the line of attack, and taking a big step back as you draw. At the time of the original tests, my thinking was not as broad-based as it is now. I was used to standing on the firing line and facing targets, planting my feet and shooting.

Later, I talked about the test with some folks at Gunsite, and they said, “we have got to get the word out.” Chuck Taylor was the operations manager at Gunsite at the time, and also an editor for SWAT magazine. He encouraged me to write about it. In March of 1983, the article appeared in SWAT magazine entitled How Close Is Too Close.

EJournal: Have you any idea how your study morphed into the so-called “21-foot Rule?” Is that a concept to which you subscribe?

The term “21-foot Rule” was not one I used. In the article, I talked about recognizing the danger zone, and about using cover or at least obstacles to slow an attacker.

A little while later, people started contacting me about it. Manny Kapelsohn was working a case where they were defending a man who had shot an attacker who was coming at him with a crowbar. Then, I think it was later that same year, Massad Ayoob wrote an article addressing these same issues. And that’s where my name got attached to it. Massad Ayoob referred to this concept of reaction, response, time, and distance as the “Tueller Principle”, and dubbed the demonstration and training exercise as the “Tueller Drill.”

Caliber Press ( referred to “How Close Is Too Close” in their second Street Survival book, Tactical Edge and used the terms “reactionary gap” and also coined the term “proxemics.” They later expanded on this in their excellent training video “Surviving Edged Weapons.” Then somewhere in the intervening years, the term “21-foot rule” crept into the lexicon. As Dave Smith at Calibre Press would say, that term was “a sticky idea:” a little concept that now, if you say 21-foot rule, most people in our field will know what you are talking about.

With that, I still think the “21-foot rule” is a poor use of terminology. Why not a call it a “rule”? Because words have meaning in the context in which we use them. What do you think of when you hear the word “rule?” “Follow the rules...” “Don’t break the rules...” “That is a violation of the rules...” In that context, the “21-Foot Rule” could be incorrectly interpreted to require you to shoot someone who is fifteen feet away and brandishing a knife. Conversely, it could be erroneously inferred that “the rule” prohibits the shooting of this same would-be slasher if he is 24 feet and nine inches away. This may be over-stating the case, but I don’t think so, as I have heard people express both of these views when discussing the subject. For example, how long do you suppose you ought to wait if a guy is marching toward you swinging the legendary 32-inch blue steel machete? Are you going to wait for him to cross some imaginary line before you act to stop the attack? And what if there are multiple adversaries? How quickly can you effectively deal with more than one?

We also need to consider: Is it really 21 feet? Do you have an accurate tape measure in your eyeball to measure the distance? In addition to proximity, variables include the physical size and condition of both the aggressor and the defender, the presence of obstacles, cover, bystanders, partners, the terrain, footing, lighting, environment, etcetera, etcetera, etcetera. All of these factors combine to create the “totality of circumstances” which will drive our use-of-force decisions.

“Rule” has a nice catchy ring, but I think it is a very poor term. I would have never called it that. Your defensive tactics should be in response to whatever the circumstances dictate! What is your drawing time? With a high-security holster, an officer may take two seconds or more just to clear the holster.

Dr. Bill Lewinsky, a consultant at the Police Policy Studies Council (, has conducted extensive studies and elaborated on these concepts using high-speed photography and reaction response time testing. His is some of the best work in the business.

EJournal: Now, 25 years later, if you were re-writing How Close is Too Close? what, if anything, is different?

Tueller: How many times have we said, “If I knew back then what I know now?” I’d stress the concept of reaction and response. What I was trying to get across is that most people don’t realize how fast an adversary can cover the distance.
I’ve seen this tested other ways, where instead of the adversary facing you, you have him on his knees, proned out or in a handcuffing position. Even then, it is surprising how fast some people can jump up and cover 21 feet.

EJournal: When you wrote it up How Close is Too Close? your article encouraged alertness; suggested withdrawing to a safer position; identified the “Danger Zone” of 21 feet and closer; moving to cover; suggested drawing the gun as soon as it is apparent danger is present; issuing a verbal challenge; and practicing the step back technique. We’ve talked about some of the other issues, what about the step back?

Tueller: When I was a new police officer in the 1970s if, during range training, someone had even proposed the idea of moving with a loaded gun in your hand, the Range Officer would have had you flogged! You planted your feet, toed the line and stayed right there. You loaded only on command and unloaded when you were done firing. It seems they were overly concerned with running a safe range, and thus were not doing a very good job of teaching officers how to win an armed confrontation. Me being a product of that type of training, I wanted to sell the idea of taking a single big step back as you draw - to gain a bit more distance from your attacker - as an acceptable technique. Of course I’ve come to realize that if one step back is good, six or eight are better if you can maintain control and move smoothly.

A lot of water has gone under the bridge since then and range training has improved. Renowned trainers like John Farnam and Clint Smith were among the first, in my experience, to have expanded on and popularized the concept of moving off of the line of attack as part of your response, although this is not as modern as we might think. You know the saying that there’s not much new under the sun? I was rereading my copy of Fast and Fancy Revolver Shooting, which was published in the 1930s. In it, Ed McGivern has pictures of how he taught officers in Montana during the 1930s to shoot on the move. At that time, he was probably considered a heretic! I’m sure most range officers thought that what he was doing was too dangerous.

So, the idea of moving and shooting is not brand new. Speaking only for myself, I think being able to move then shoot, shoot and then move again is tremendously important. So is moving when you see a potential threat, so you are not standing where the attack was directed. That way you can get inside your adversary’s reaction time, forcing him to react to what you are doing.

I have mixed feelings about shooting on the move. I know some people who have trained diligently, and who can shoot reasonably well while moving. For most of us, though, it probably is not a good idea to try shooting while you are moving. Moving, then shooting and getting some hits, then moving again, assessing and finding additional threats, that’s probably better.

EJournal: Finding additional threats? How do you train to overcome tunnel vision?

Tueller: Once you’ve engaged the threat, if it disappears, runs away or falls down, you need to get the gun out of your face, force yourself to breathe and move your head and eyes. The focal attention gets really intense when shooting, and that’s something we encourage by teaching that to get good hits you have to focus on the front sight. Because your vision is really tunneled in while shooting, you must recognize the tactical imperative to get gun out of your face when the shooting is over.

It helps to physically move your head and upper torso. Like anything else, until you have trained to do it and built it into your routine, it won’t happen naturally. People have successfully used this method, and their feedback after confrontations is that they used it and that it worked, but you have to develop the habit before needing it.

EJournal: Most of our readers are private citizens who practice concealed carry. With the gun hidden under layers of clothing what precautions should be observed in the presence of possible attack with a contact weapon?

Tueller: That goes back to the issue of reaction and response time. The more time you need to physically access your defensive weapon and put it into action, then you need to have that much more distance that an adversary with a contact weapon would have to cover. The thing to do is to find out how long that is.

You could test this with a dummy gun and have a friend role play a bad guy to see how much distance would be covered before you could draw. Another variation I’ve seen on the Tueller Drill is done on a live fire range. The guy representing the attacker starts standing next to the shooter, but runs away from the shooter to the right, left or rear. When he pushes off from the shooter, the shooter draws and engages a target down range. The role player will drop a hat or some object when he hears the first shot. That marks the distance he covered before the first shot. This is something you can do very safely. And please remember: just firing a shot does not mean that the fight is over.

EJournal: So you mean that the slower drawing speed, requires longer distance awareness?

Tueller: No defensive weapon or plan is good enough if we are not alert enough to recognize that we have a problem. I teach this as the four “As” – aware, alert, act, and alive. This applies to everything—daily life, driving, and to a self-defense situation.

“Aware” means you recognize, believe, accept and understand that there are various kinds of dangers in daily life, and that – yes – it really can happen to you. If this is your mind-set, it is easier to remain properly alert.

“Alert” means that you are attentive to your environment, so your physical senses and intuition are turned on and tuned in. Jeff Cooper listed alertness as the first principle of personal defense (Ed. Note: See Cooper’s book Principles of Personal Defense When you believe it can happen to you, your brain is geared to look for things that don’t look right; then you can avoid them. In the book The Gift of Fear by Gavin DeBecker (, he writes that to “fear less,” you should trust your feelings.

Then “Act.” Take appropriate action based on indicators your brain picks up, often at the subliminal level. Even though our modern, civilized conscious mind isn’t always able to recognize what the threat is. Being prepared to act can be based on “crisis rehearsal”. Do some mental imaging, do some training, visualize and mentally see yourself defending yourself, successfully surviving and prevailing. No one knows exactly what we may do, but if we have trained, we have a pretty good idea of our responses. We will respond as we have trained. Act on the threat indicators, and you can remain alive.

And that’s the final “A” – Alive. This is not all doom and gloom. There is more to being alive than just avoiding threats and danger. Yes it’s often a dangerous world, but if you are paying attention to your surroundings - not just walking around looking at the cracks in the sidewalk - you will also be more aware of the beauty all around. You’ll see the flowers, the sunshine, the kids playing, because you’re not focused on yourself and your problems. Keep your head and eyes up and pay attention, and enjoy.

EJournal: Your original article mentioned issuing verbal commands, and a lot of people carry alternative defenses like pepper spray. What about the time it takes to review our options and decide which to use? How could the human brain make a choice quickly enough before that second-and-a-half are consumed?

Tueller: You will see slower response times with a greater number of choices. With more options, comes more information you have to process. This is a two edged sword. Sometimes, less-lethal options, or distractions like pepper spray, have their place. But it does complicate the overall problem. Be familiar with whatever tools are in your took kit, and know how and when to apply them.

Thirty years ago, when I was a young cop, we carried a pistol and a baton. Those were your options. Now we have pepper spray, Tasers, strobing flashlights, etc. It can be kind of like choosing the between needlenose pliers or channel lock pliers, or using a socket wrench or a pipe wrench for a certain kind of job. Having lots of tools can be a good thing, but still, the more choices you have to make, the more time it takes brain to process and act on the decision.

EJournal: Does that mean instructors should advise against using some defense tools or tactics?

As instructors we shouldn’t presume to tell people what to do in every situation. What I can tell students is what I’ve learned from experience, and from research and study. But I can’t tell you if you should always fight back, since in some circumstances it may not be the best option. It is true that most studies of armed assault show that fighting back works more often than it fails, but I still can’t tell you what you should do in any specific situation.

You need to believe it can happen to you. You need to recognize dangers in your vicinity, trust your feelings, and act based on your knowledge, experience and training.

EJournal: Thank you, Dennis, for sharing your knowledge and experience with us.

Ed. Note: Dennis Tueller has agreed to lend his expertise to the Armed Citizens’ Legal Defense Foundation Advisory Board, for which we are very grateful. In this role, he will join other advisory board members in reviewing requests for financial assistance with legal costs from members who are being wrongfully charged after a lawful act of self defense.

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