It has been nearly forty years since Dennis Tueller’s ground-breaking research showed an attacker could close a gap of 21 feet in a second and a half on the average, from a standing start.  His work has since saved countless lives on the street, and countless careers in court.

Yet, still – still! – we see people corrupting and misunderstanding the principle, which may be the single most proven element of what is now called “Force Science,” a term coined by Dr. Bill Lewinsky.

Here, Dennis himself explains it clearly. Thanks to VirTra for posting it:

Or watch video here.

28 COMMENTS

  1. Oughta be required understanding for news editors/writers and others who believe that every situation can be deconflicted.

    • WR Moore,

      There out to be a required class in journalism school entitled, “Introduction to Firearms.” Why? Because firearms are in the news every day, whether the story is crime, war, an accident or suicide.

      • I went to journalism school, worked as a reporter for many years. An “Introduction to Firearms” class would be Brady, Everytown, Giffords, etc. It is a lost cause to think these people will change their minds on firearms or want to be educated by the wisest people in training. They are foaming haters of the 2nd amendment. Some used to at least make an attempt to pretend they didn’t, those days are long gone. The only way to change the culture of journalism is for conservatives/libertarians to take it over, and good luck with that happening any time soon, if at all.

      • Thanks, Colonel Travis,

        That shows how prejudiced against guns the media are. I was thinking “Introduction to Firearms” would focus on how guns work, but you are right about how the material would be taught, and by whom.

        Contrast journalists’ attitude to mine. I am not mechanically-inclined, yet I realize that machines are part of everyone’s life. So, when I was 20, I borrowed a book from a friend which taught me how cars work. I reasoned that since I was in cars every day, I needed to understand how they work. That knowledge has been a big help to me, even though I can’t fix a car. Even people who know how to fix modern cars can’t do it because they don’t have the tools, but knowing how machines work is handy, maybe even essential. See http://www.howstuffworks.com

        It seems to me that if you are not good at math, science, technology or business, then you don’t belong in this modern world. I feel that way all the time, because I am not good at those subjects. I do my best, and when I have a problem I can’t solve, I get help. Journalists are comfortable with their ignorance. We notice their mistakes, and it makes them look unprofessional, but it doesn’t matter, because they have more power to influence public opinion than we have. But, there are a lot of gun owners, and even more people who distrust the media.

      • Roger Willco, I have the same curiosity and desire to know things as you. Although, I didn’t apply it to cars except change brakes and oil and plugs and that’s about it! Everybody has their thing….

        Unfortunately, that mindset doesn’t exist in the majority of the population any more. In journalism, it’s all about advancing a one-sided cause. To them, it doesn’t matter what it takes to do it. It truly disgusts me because a country built on freedom and liberty cannot survive this kind of manipulation, which is, of course, the point for these people.

      • Colonel Travis,

        I know some people are attracted to the idea of being a revolutionary. That is why some people like Che Guevera. To them, the idea of changing the world for the better is exhilarating, and the idea of being famous boosts their egos. Once, on the radio, I heard Ron Kuby admit that he found the idea of being a revolutionary attractive.

        Our Founding Fathers were revolutionaries, and few people thought it was possible to defeat Great Britain back then. They gambled, and won. Quite a feat. And, when they were working on the new Constitution in 1787, Jefferson called them, ” . . . an assembly of demi-gods.”

        Marxism is the opiate of the intellectuals. (That’s a book.)

  2. Thanks for sharing this Mas. Mr Tueller clarifies some questions I’ve experienced over the years, and the two of them provide a better ex than I probably would have. I’ll share this video….

  3. I was extremely fortunate to find instruction from folks like Tueller and you Mas as I started my CC training. I believe there are three stages to this principle, the first is simply to understand it, the second is to perform it, and the third is realizing a sub-second first round may not be enough. Awareness beats speed, avoidance beats awareness.

    • Yep. Have your hand on pistol grip and start your hopefully clandestine draw while you call out “Hands!” & dash or dive for nearby cover that you have previously identified. When you happen to find yourself in an outdoor drug dealer area you really need to maneuver like Hiawatha when you can, until you can exit that area. Better to have in your hands a 12 gauge loaded with buckshot in a stand-off. Too many drug pushers seem to be loaded too, mostly on their own product. They really have little common sense in the moment, and may say or do anything.

  4. I have been teaching the State mandated content for permit to carry candidates in Minnesota for 20 years now. This is the finest teaching video I have ever seen in terms of what “The Tueller Principle” is as well as the term “”OODA.” I just forward it to our Church Security Team. Thanks so much.

  5. Not only do all people who carry concealed need to understand everything explained in this clip, we need to document our understanding. Email this link to a friend and encouraging them to watch it and explain why. If you’re ever involved in a use-of-force event, it could demonstrate your understanding of why you had good, objective reason to believe there was an imminent threat of death or great bodily injury at the time of the event. Thanks for posting this, Mas.

  6. I witnessed the truth of the 21’ rule last week. Fortunately no blood drawn.
    Working in a publicly accessible area and focusing on work. Had an admitted drug user quickly walk not even run. 27 feet from entry to contact point, yes I measured. To pushing my coworker with a broom he picked up while advancing.
    Fortunately we both have had training experiences that helped. Kept the dude calm and kept the interaction low key.
    BUT.. what if he didn’t have the same intention. I could not have saved my friend. I could not have reacted fast enough.
    I work public accessible areas every day. I get wrapped into my work and my observation bubble shrinks to what I am working on. It has to to be that way to be good at my job. And to do my job safely. I look for other social abnormalities to key me into threats such as louse voices or movement of those around me.
    This time…. Nothing. He just was there. In my space before I could react. That is some thing I’ll never forget.

    • Jake C,

      You are correct. If you are concentrating on your work, you can’t be scanning 360 degrees looking for threats. Ideally, you would have guards if you were working in a city. Maybe, if you have co-workers, one worker could “take a break” and be the lookout, while the rest work. Knowing how capitalism works, I’m sure your boss doesn’t want to pay for anyone who is not working. He wants efficiency more than safety. I don’t blame him, because safety (guards) cost money.

      Wouldn’t it be nice if citizens were protected by government-paid, tax supported, police? Oh yeah, that’s how it used to be, until Democrats ruined everything. Stupid voters.

  7. When I’m watching a movie, and the hero is running straight down the middle of the road being chased by an automobile, I have been known to tick off the rest of the audience by grumbling, “Go right or left, you idiot!”

  8. larryarnold
    Gotta suspend disbelief with any film. I once span the car round and found myself facing incoming traffic on the motorway. it was 4am (why i misjudged the bend) so no harm done. When my wife rang me that afternoon she could tell I was still shaken.
    In films a waitress gets caught up in gunfights, car crashes, car chases, explosions… and is perfectly calm. When I wore blue we could tell who’d been in a fight. Their report was so badly written, they were still shaking with adrenalin.
    To stay on subject:

    J Edgar Hoover said ‘the man who is not justified in shooting to kill, is not justified at all’.
    That’s true.
    But is shooting to make imobile ever a good idea? In the ‘chap with a baseball bat walking towards you from 30 feet away’. Could one probably stop him with shots to the legs?

    • “But is shooting to make immobile ever a good idea?”

      Quote of the Day:

      “It’s a lesson I learned a long time ago. A man worth shootin’ is a man worth killin’.”

      Henry Fonda (playing the character of outlaw Bob Larkin) in the Western Movie ‘Firecreek’.

      In this movie, the character, Bob Larkin, shot to immobilize his opponent and ended up regretting this decision (for a short space of time) before being killed himself.

      In modern “legal Approved” language, I would update this to say:

      “A man worth shooting is a man worth stopping ASAP”.

    • @nicholas kane:

      IANAL, but my understanding is that shooting a man anywhere is deadly force, even if you aim at his foot.

      It’s why trainers teach to shoot to stop the threat. If that can be accomplished by immobilizing, great. But recognize that if a man is attacking you with a gun and you shoot him in the leg and he falls, he still has a gun; the threat is not stopped. If he has a knife/club/bludgeon/etc., you might be out of immediate danger — as long as you don’t get too close — but the guy is still a threat. (And that’s not going into the high-on-drugs guys who seem to just ignore all wounds and keep coming.)

      But legally, regardless of where you aim, shooting is deadly physical force, which is usually defined along the lines of “force which is likely to cause death or great physical harm” (not that it always does, but it’s likely to). Immobilizing someone through injury is included in the definition of “great physical harm” (or your state’s analogous verbiage), whether in defense (like you propose) or in the course of a crime (beating someone unconscious in order to rob them).

      If you’re going to go the route of shooting to immobilize, it had better be to stop an imminent threat of death or great physical harm. And as extremities (legs, ankles, etc.) are much smaller and quicker targets and much harder to hit, if the situation requires shooting, you’re often better off shooting at center mass.

      But again, IANAL, and this is just my understanding.

      • Archer,

        IANAL either, but I think you would make a good one. Your post is very good.

        I will never forget hearing about a young man being shot in the leg, and dying from it. This happened within the past 20 years, and the man was shot in a city, so help should have arrived very quickly. How did he die from a leg wound? The bullet pierced his femoral artery, and he just lost so much blood so quickly that there was nothing the EMTs could do for him. I am not a doctor, but I suppose the immediate application of a tourniquet may have saved that man, I don’t know. But it shows how, even in modern times, in a modern city, a leg wound can be fatal, even for a young man.

      • @Roger Willco,

        Thanks for the compliment! I appreciate it! Like “Law of Self Defense” lawyer Andrew Branca says, “You carry a gun so you’re hard to kill. Know the law so you’re hard to convict.”

        Yea, I’m not a doctor or EMT, either, but IIRC, severing the femoral artery causes such rapid blood loss that the person loses consciousness in 30 seconds, and bleeds out in under 3 minutes.

        What’s the response time for EMS? Even a lightning-quick sub-4-minutes is too slow for this kind of wound. Getting the femoral artery severed on the steps of a level 1 trauma center might be too slow.

        The immediate and proper application of a tourniquet might have saved that young man, IF the wound was low enough on the leg for the TQ to stop the bleeding. If it was up in the groin area where a TQ can’t get on it, there’s little anyone could have done.

        So yeah, back to nicholas kane’s question: Shooting in the leg is no joke; legally, it’s still very much “deadly force”, and for very good reason.

  9. I avoided having to use force against a suspected meth head who was maneuvering to close the gap by the simple expedient of moving behind my truck. He didn’t display a weapon and hadn’t gone into charge mode but I perceived a threat. After I got behind the barrier, he backed off.

    I am not a cop but if you looked up meth head in the dictionary, there would be a picture of this guy.

    • Danno,

      Better yet, shoot the weapon out of his hand, like the good guys did in early Western films. HA!!! HA!!!

    • Would that be the same POTUS who advised to fire two blasts (from a double-barreled shotgun) into the air to scare off intruders, and to shoot through the front door without first identifying who is knocking?

  10. Just this week in one of his video presentations, “Law of Self Defense” lawyer Andrew Branca seemed to be saying that up to 21 feet was a danger zone with the implication that 22 feet was not. I hope he misspoke.

    • IANAL, but as I understand it, 21 feet is a danger zone because an average person with a knife (or other stabby implement) can cover that distance and deliver lethal blows in the time it takes an average responder to draw and fire two aimed shots.

      Does that make 22 feet “safe”? Not necessarily, nor does it necessarily mean 20 feet is dangerous (see the two instances of “average” in the above sentence; one or both of you might be faster or slower than average).

      But because the Tueller principle says “21 feet”, prosecutors like to say 22 feet is safe. As if a responder can say “time out”, pull out his measuring tape, and find out exactly when an attacker is inside the 21-foot “danger zone”. And as if career criminals were never athletes in school.

      Tueller’s principle was never intended to be a hard-and-fast rule (see “average” above, again). But like so many aspects of criminal law, it’s not necessarily what the facts are, but what spin a prosecutor can make a jury believe.

      Mr. Branca may have left the implication that 22 feet is “safe”, and probably did not misspeak. But that’s not him; that’s what a sleazy prosecutor will do given half a chance. Better for us to be prepared for it.

  11. Great to get the conceptual history from the source. My police academy definitely taught the Tueller drill improperly. Similar to how Col. Cooper’s el presidente has been “bastardized” into something else. I’ve heard many people call it useless or unrealistic due to the generous parameters, yet that bypasses the original intent and logic of that drill. Teachers need to know both the theory and application to better serve their students, but like Clint Smith says, there is a difference between an instructor and a teacher. The comments here continue to enrich the articles, much appreciation to all.

  12. Hey one more point, check out Donut Operator’s latest video on his YouTube channel for a perfect example of the reactionary gap. He shows an Oregon state trooper encountering a man on foot on the interstate stopping traffic and pointing a handgun at random motorists. Both the bodycam and dashcam capture everything in graphic and dramatic fashion. An off duty Deputy comes to his aid, which is also a perfect example of the curriculum in MAG-20. You can also compare how this oregon trooper used cover and tactics compared to the FTO using a rifle and how he capitalized on the (less than ideal) cover and concealment of the tiny flower box to turn the tables on the mass killer in Louisville bank mass murder. So check out Donut’s recent video on that incident, it has a link to help the grievously wounded rookie Louisville officer too. These videos just came out and i found them to be prescient exemplars of what we’ve been discussing here.

Comments are closed.