The Double Tap.
At SHOT I made a passing comment to Pharmacist Tommy that, in the context of defensive shooting, practicing double taps was a tacit admission that a person wasn't able to control their gun. He looked at me quizzically, as I'm sure you're doing right now.
(Let's get some terminology out of the way. Most people shooting double taps are firing two rounds in quick succession with one sight picture. Adherents to the so-called "Modern" Technique would scream that the term is used incorrectly, and that they are actually shooting 'hammers'. I'll concede the point, in the same way I concede that the Battle of Bunker Hill was in fact fought on Breed's Hill - you'll note it's made no difference in elementary school history lessons, however. I'll continue to use Bunker Hill and double tap to describe what the majority hold that they describe, because arguing the point wastes my time and doesn't change the outcome anyhow.)
Let's start with a question: why practice the double tap as a defensive tactic? When I watch surveillance and dashcam videos, regardless of the training level of the shooter, I don't see the stylized double tap. What I see instead, very consistently, is a string of fire without artificial pauses. After all, bullets are what stops bad guys -- and the faster those bullets get to him, the better.
If you need to shoot your attacker six times, and choose to do so with three double taps, that means the half-second pause between those strings gives him a full second to hurt you more. How many bullets can come out of his gun in one second? How many critical stab wounds can he inflict? How far can he move? Giving the bad guy any extra time is counter to your own self interest.
How about double-tapping, then assessing (as is still the recommendation in some training backwaters)? The answer is that there is no way to know ahead of time how many shots it's going to take to make your bad guy go away. That being the case, why on earth would you stop shooting at an arbitrary point if a threat is present? The time to asses is after the threat is no longer in front of your gun, whether that takes one, two, or five rounds. Practicing to always do that at two rounds means that if your fight goes longer and you stop to make your well-rehearsed assessment, you're exposing yourself needlessly to danger.
I could go on, but my point is that the double tap makes no sense in the context of surviving a lethal attack. The logical practice routine would be to always fire a random-length string of shots: two, three, four, and perhaps even occasionally five or six. Mix 'em up; don't get locked into any one pattern.
The double tap really doesn't have a use in defensive shooting, yet people all over the country continue to practice it. I believe the answer is simple, and I've observed it in action: if you ask any random shooter, regardless of his or her proficiency or training level, to shoot a string of three or four or five rounds at the same cadence (with the same "split time", or elapsed time between shots) as the double taps they're flinging downrange, the chances are almost certain that they won't be able to do so.
What usually happens is that the first two shots land in acceptable proximity to each other, but the third will climb significantly and the fourth is usually off the target. In order to land all their shots inside whatever reasonable target area is chosen, they need to slow down - sometimes significantly. In other words, they can't control their gun at that inflated rate.
Now, just about everyone will be faster at the double tap than at an extended string of fire. The point is that the longer strings of fire are what are most likely in the context of a defensive shooting, because the natural reaction is likely to be shooting until the threat goes away. If the gun can't be controlled in such a realistic or plausible shooting scenario, then that shooter needs a different gun (or much better technique) instead of gaming his or her practice to artificially inflate competence.
Shooting double taps instead of more realistic strings serves as proof that one cannot control the gun for the use to which it is likely to be put. It's up to the shooter to recognize, admit, and change.
-=[ Grant ]=-