The Latin tag "Diligentia, Vis, Celeritas" (DVC) was coined by the late, great Jeff Cooper. It means "Accuracy, Power, Speed", and summarizes the qualities needed for a shooter to prevail when push comes to shove. For some reason this triple concept has fallen out of favor these days - at least, among the general shooting public, and among many of the shooting schools out there (although Cooper's own school, Gunsite, and Thunder Ranch still teach and maintain the tradition).
However, all three elements are vitally important. When I say that, I'm not speaking theoretically. In eighteen years living and moving through various conflict zones in sub-Saharan Africa, I was present at something over a hundred incidents involving the offensive and/or defensive use of firearms: a dozen or so as an active shooter, and many more times as a witness or reluctant, unarmed participant. In the latter incidents, I probably broke several land speed records getting away from danger and/or to cover or concealment, and I'm not ashamed to admit it! As Clint Smith of Thunder Ranch has said, "Incoming fire has the right of way". Most of the time, I took care to give way to it - apart from a few occasions when it moved faster than I did, and I still carry the scars. So, when I emphasize DVC as absolutely critical to survival when the proverbial brown substance hits the rotary air impeller, I'm not just saying it. I've learned the hard way that it's true.
Therefore, we need to take this into account when planning, training and equipping ourselves to protect our loved ones and our homes. We can't be theoretical about it; we have to actually put these elements into practice. Every one of them is equally important.
Diligentia (accuracy) is self-explanatory; if you can't hit a criminal trying to harm you or your family, you can't stop him. However, a hit just anywhere (unless with something very powerful, such as a shotgun) probably won't stop him. It takes a central nervous system (CNS) hit (i.e. the brain or spinal cord) to shut down an attacker's nervous system and stop him dead in his tracks. A solid hit to the heart or vital blood vessels will usually stop an attacker within 30 seconds or so, but during that time he may still be dangerous, particularly if he's close enough to reach you; therefore, such hits are not good enough for someone within a few yards of you. He has to be stopped right then and there. That means training to hit the CNS rapidly and repeatedly (because your first shots might not be right on target, and you can't afford to pause, waiting for him to fall over. As Jim Higginbotham has put it, "Keep shooting until the target changes shape or catches fire!" Inaccurate fire won't have the desired effect.
Nevertheless, lack of accuracy is appallingly common. Witness the innumerable situations where cops fire dozens or scores of rounds at a criminal before putting him down. The majority of their bullets usually miss their intended target. Cops can generally get away with it if a stray round hits someone; they're covered by the doctrine of qualified immunity. However, we aren't. Every bullet we shoot has a potential lawsuit (or even a criminal charge) attached to it - not to mention the moral guilt if it takes an innocent life. That's yet another reason to do our best to make sure our bullets go where we intend them to go, and nowhere else.
Vis (power), the second element of the triad, is also self-explanatory. If the level of force applied in self-defense is not enough to prevail, it won't do anything to help us. Hitting a mugger with a feather pillow might make him laugh, will probably make him mad, and will almost certainly result in greater injury to us. Hitting him with a Louisville slugger, or a brick, would have rather more effect, but still puts us too close to him - he'll be able to hit back. A firearm means we can stay further away from him, and the cartridge in that firearm will have to generate enough power to penetrate obstacles (e.g. heavy winter clothing, layers of body fat and muscle, bones, etc.) and reach the vital organs we have to hit to stop the fight. A .22LR cartridge will undoubtedly kill someone, but it doesn't pack much energy or mass, so it may take several hits and several minutes to take effect if we miss a CNS hit. That's far from ideal. A big heavy bullet may miss the CNS, but still impart enough shock and pain to the attacker to cause him to stop what he's doing (provided he's not so hopped-up on drugs that he can't feel his injuries). I'll take that. As a general rule, the minimum power considered acceptable in a defensive handgun cartridge is .38 Special in revolvers, or 9mm. Parabellum in semi-auto pistols. There are many advocates of modern smaller-caliber rounds, but actual shootings using them, and post-mortem autopsy records, are far fewer in number than the older, larger rounds; so I'll stick with the historically tried-and-true cartridges. YMMV, of course.
Celeritas (speed) is often derided as being "competition-minded" rather than practical. Some quote the Old West gunfighter maxim that "Speed's fine, but accuracy's final". That's certainly true. However, in a gunfight things can happen amazingly fast, particularly if an attack is launched from close range. The well-known Tueller Drill demonstrates that a knife-armed attacker can cover a 21-foot distance and stab his victim in one and a half seconds. Some shooting schools incorporate that into their training, so that a student stands 21 feet from a forward-moving target, his gun holstered at his side. As soon as the target starts speeding towards him, he has to draw and shoot and score a stopping hit (usually CNS) before it reaches him. A great many students find that very difficult, if not impossible. If a mugger steps out from behind a building as you approach a corner, and lunges at you, you may have less than that time to react. Will you be able to?
(If you haven't studied and practiced the Tueller Drill, or want to know more about the critical importance of reaction time, watch this video. It may save your life.)
Putting all three elements together, we can see that they're the key to surviving an armed encounter. Lapses in any one of them might possibly be enough to lose the fight; lapses in any two out of three make that a probability; lapses in all three make it a virtual certainty. Are we training to shoot an adequately powerful weapon, accurately, at high speed? That's what it amounts to. Casual, untrained plinking won't do it. I've seen any number of "weekend shooters" bring their handgun to the range (still in the box it came in), fire off 50 rounds of the cheapest practice ammo they can buy (landing all over the target, not in a tightly aimed cluster), and then go home thinking they're ready to defend themselves. They haven't practiced drawing from a holster or pocket, or shooting on the move, or trying to hit a moving target. If they get picked on by a violent criminal at close range, or cornered in their house by a home invader, will they survive? I suggest the odds are against them.
A complicating factor is if there are multiple attackers. While you're concentrating on neutralizing one of them, the others will be doing their best to neutralize you. That's why it's very important to have speed on your side; switching from one target to another, hunting for cover or concealment, and avoiding charging attackers. It's all very well to say "slow is smooth, and smooth is fast", but a lot of people stop at "slow" and never try to speed up. That can be fatal. Practice is needed.
Another factor is our own physical fitness and ability. I'm getting older now. I find it hard to see standard iron sights unaided; I can't move very fast, thanks to a long-standing disabling injury; and having had two heart attacks, a fused spine and nerve damage, I'm very unlikely to be able to use fisticuffs or another fighting technique man-to-man. I have to choose a weapon that will keep my attacker(s) at a distance, put them down before they can reach me, and allow me to move to safety at my slower, more awkward pace. That makes my defensive problem much worse than a young, fit person who can move so much faster and more easily than I can. I daresay some of my readers may have similar problems.
DVC is a series of concepts to live by. Each of us needs to consider where we fall on that spectrum, and seek out training and practice to improve our standing if at all possible. Given the rising crime we see all around us (more about that later), we're playing with fire if we don't.
Peter