The Tueller study is credited with first establishing the importance of maintaining a “reactionary gap”. This article by Dennis Tueller first appeared in the March 1983 issue of SWAT magazine.
Here's the original article in its entirety. "How Close is Too Close?", by Dennis Tueller:
The "good guy" with the gun against the "bad guy" with the knife (or machete, axe, club, tire-iron, etc.). "No contest", you say. "The man with the gun can't lose." Or can he? A great deal depends on his ability with that gun and the proximity of his opponent.
If, for example, our hero shoots his would-be attacker at a distance of 20 yards, he loses. Not the fight, you understand, but most probably his freedom because he will almost certainly be charged with murder. The only thing that justifies your shooting another human being is the immediate need to stop him from trying to kill you (or someone else), remember?
If, on the other hand, our hero waits to fire until his attacker is within obvious striking distance, he may still lose. His shots may not stop his attacker instantly enough to keep him from using his knife.
So, what is the answer - just how close is too close?
Consider this. How long does it take for you to draw your handgun and place two center hits on a man-size target at seven yards? Those of us who have learned and practiced proper pistolcraft techniques would say that a time of about one and one-half seconds is acceptable for that drill.
With that in mind, let's consider what might be called the "Danger Zone" if you are confronted by an adversary armed with an edged or blunt weapon. At what distance does this adversary enter your Danger Zone and become a lethal threat to you?
We have done some testing along those lines recently and have found that an average healthy adult male can cover the traditional seven yard distance in a time of (you guessed it) about one and one-half seconds. It would be safe to say then that an armed attacker at 21 feet is well within your Danger Zone.
Even if your draw and shots are perfect, you are cutting things awfully close (no pun intended). And even if your shots do take the wind out of his sails, his forward momentum may carry him right over the top of you, unless, of course, you manage to get out of his way. And if you are confronted with more than one assailant, things really get tricky. So what's a pistol-packing person to do?
Having analyzed the problem, the following suggestions come to mind: First, develop and maintain a healthy level of tactical alertness. If you spot the danger signs early enough, you can probably avoid the confrontation altogether. A tactical withdrawal (I hesitate to use the word "retreat") may be your best bet, unless you're anxious to get involved in a shooting and the consequent legal hassles which are sure to follow.
Next, if your "Early Warning System" tells you that a possible lethal confrontation is imminent, you want to place yourself in the best tactical position available. You should move to cover (if there is any close at hand), draw your weapon, and start to plan your next move.
Why use cover, you may wonder, if your attacker is using only a knife? Because you want to make it hard for him to get to you. Anything between you and your attacker (trash cans, vehicles, furniture, etc.) that slows him down buys you more time to make the appropriate decisions, and, if it becomes necessary, more time to place your shots.
I suggest you draw your weapon as soon as the danger clearly exists. There is no point in waiting until the last possible second to play "Quick-Draw McGraw" if you recognize the threat early on. Also, the sight of your "Equalizer" may be sufficient to terminate the action then and there.
The purpose of the pistol is to stop fights, and whether it does so by dropping a thug in his tracks, or by causing him to turn tail and run, your goal is accomplished, is it not?
At this point it might be advisable to issue a verbal challenge such as, "Stop"', "Don't move", or "Drop your weapon!" It may work, and even if it doesn't you'll be developing your legal case for self-defense by showing that you did everything you could to prevent a shooting. If all goes according to plan, the odds are that by now you will no longer have a problem, your attacker having remembered he had a more pressing engagement elsewhere.
But, as we all know, things seldom go according to plan and the ideal circumstances previously described are probably not the norm. For example, if this goon tries to throw his knife (or other weapon) at you, what do you do then?
Realistically, knife-throwing is something of a gallery trick requiring specially balanced knives and a pre-measured distance to the target. Suffice it to say, however, that if your attacker is within effective throwing range he will almost surely have encroached into your Danger Zone. This throwing business does create something of a timing problem, for, if you fire after he has thrown his weapon, you may have difficulty convincing a jury that you fired in self-defense since technically you were not in jeopardy if your former attacker is no longer in possession of a deadly weapon. Something to consider, and just one more reason to use cover if it is available and time permits.
Sometime, of course, despite your best efforts, you could find you are suddenly, at close quarters, the intended victim of some lunatic slasher. If you are an expert in one of the many martial arts, you may opt to go at it hand-to-hand, and if you are in this category you do not need advice from me on how to do it. So, we'll get back to the use of the handgun for solving the problem. What it all comes down to now is your ability to smoothly and quickly draw your pistol and hit your adversary, and do it all reflexively. And the only way to develop these reflexes is through consistent, repetitive practice, practice, practice.
Practice so the right move comes automatically.
One thing you should practice, with this kind of encounter in mind, is the step-back technique in which you take a long step to the rear as you draw. This puts another three to four feet between you and your attacker, which may be just enough to make the difference.
Remember, the greater your skill with your weapon, the smaller your Danger Zone will be, but only if that skill is coupled with good mental conditioning, tactical planning and alertness, because no amount of skill will do you any good unless you know that you're in trouble.
Skill at arms and proper mental attitude. that's the combination that will make you the winner in a "Close Encounter of the Cutting Kind".