Bullet and cartridge effectiveness for self-defense

We've addressed the topic of caliber, cartridge and bullet selection on numerous occasions in the past.  You'll find most of the relevant articles linked in the sidebar, in alphabetical order by title.  In particular, I recommend the three part series on 'The Myth of Handgun Stopping Power' (the link goes to the first article in the series, which contains links to the next two).  It covers most of the bases.  I also highly recommend this outstanding discussion of the best choices for self defense ammunition.

In this article, I'd like to address a few issues that still cause controversy, and which I think are not well understood in the context of today's technology-driven 'solutions'.  Sometimes those solutions work very well.  At other times . . . not so much.

In the discussion recommended above, we find this chart showing the penetration of typical defensive bullets in ballistic gelatin, fired from various cartridges.

Their effectiveness looks very similar . . . and in that test medium, under laboratory conditions, it is.  However, gunfights don't take place under laboratory conditions.  The size and mass of the person being shot varies from individual to individual;  they can be struck in bare flesh, or through a T-shirt, or through several layers of heavy clothing; the bullet can go through flesh only, or flesh and bone, or through a series of layers of fat, muscle, bone, etc.  The individual may have more or less pain resistance (if he's hopped up on drugs, he may not even realize he's been shot);  he may have been shot before, and know from experience that he can fight on through the pain (as is often the case with street-wise thugs);  he may turn and run, or he may continue his violent attack, necessitating more than one shot.  Above all, the bullet has to hit a vital target area (either the central nervous system or the core circulatory system) to shut him down.  Peripheral hits may slow him, or make him angry, but they won't stop him fighting if he's determined to go on.  That chart of bullet performance simply can't cater for those variables.  Ballistic gelatin can't reproduce their effect on a person's performance.

That doesn't mean that the chart above is invalid.  It's entirely valid as a measure of bullet performance under identical conditions in a laboratory environment.  As far as a 'scientific' test goes, that's about as good as it's going to get.  I use the result of such tests in selecting my defensive ammunition, and as improved rounds hit the market, I tend to assess their performance, as measured by such tests, and upgrade my selection if the improvement is sufficiently great to warrant it.  Let me give you a couple of examples.

• At the time of writing, my standard carry load in 9mm. Parabellum remains Winchester's Ranger-T 127gr. +P+ JHP load, catalog number RA9TA.  However, Federal's more recent HST 124gr. +P JHP load, catalog number P9HST3, is establishing an excellent reputation in law enforcement use, fully equal to the Winchester load.  Since RA9TA is becoming harder to find, when I next need to stock up on 9mm. defensive ammunition, the Federal load is likely to get the nod.
• In .45 ACP, two rounds stand out from the pack.  One is Hornady's Critical Duty 220gr. FlexLock +P round.  It appears to expand less than equivalent cartridges from other manufacturers, but offers better penetration in many cases.  Indeed, the Critical Duty range as a whole is the only ammunition to successfully penetrate all the FBI's test barriers and still perform according to the agency's specifications.  That's a significant achievement.  The other round is Federal's Tactical HST .45 Auto +P JHP, catalog number P45HST1.  This is performing very well in law enforcement use.  Reports I've seen indicate it's penetrating almost as deeply as the Hornady Critical Duty load, while offering somewhat better expansion.  I'm testing both in my .45 ACP pistols, and would feel well equipped with either of them.  Right now, due to availability alone, the Federal load is in my pistols, but I'll be equally happy to carry the Hornady offering.

The question some readers are doubtless asking already is, "If the ballistics gelatin tests show that 9mm. bullets are performing roughly as well as .45 ACP bullets, why would he use both cartridges?  Why not just standardize on one of them?"  Well, therein lies a tale.  Each cartridge has advantages and disadvantages.

The 9mm. round is smaller and lighter than its .45 ACP equivalent.  It produces less recoil, thus enabling less well trained and/or experienced shooters to master it more readily.  It's faster, making it easier to design expanding bullets for it.  It's cheaper than .45 as far as practice ammunition is concerned (half to two-thirds as much, usually), making it cheaper to train.  However, in so-called 'ball' or solid ammunition, it's typically been only about half as effective 'on the street', round for round, as the bigger cartridge.  Hollowpoint ammunition has tended to level the playing field somewhat, but not entirely.

The .45 round is bigger and heavier than its smaller counterpart.  It 'kicks' harder in a handgun of equal weight when compared to the smaller round, making it more difficult to control.  However, even with traditional 'ball' ammunition, its greater weight and momentum makes it hit considerably harder than the lighter 9mm. bullet.  Old-timers will recall the anecdotal claim that a single solid hit with .45 hardball stopped a fight about half the time, and two or three of them were usually sufficient, whereas one needed at least double that amount with 9mm. ball.  Recent combat experience in Iraq and Afghanistan, where ball ammunition was used by the US armed forces, has borne this out.  There are myriad tales of the lighter round failing to put down an opponent, even with half a dozen solid body hits.  Some people got their hands on .45 sidearms by hook or by crook [usually the latter], and anecdotal reports indicate that they were much more successful with them.  (The US armed forces recently announced they would issue hollowpoint ammunition with their new pistol, largely as a result of this experience, to try to improve the performance of their handgun rounds.)

A bullet will do a certain amount of damage inside the body (see the 'wound channels' produced in ballistic gelatin in the above illustration), but that damage has to take effect before it can stop someone fighting.  A man who's truly determined, or fanatical, or hopped-up on drugs, or in a fighting rage, can absorb a heck of a pounding before he goes down.  Here are a few actual cases to prove that point.

• This two part analysis of the 1986 'Miami Massacre' (read both parts!), as well as this analysis of how that gunfight sparked a revolution in ammunition design and testing that's produced the much more effective rounds available to us today;
• This analysis of a police shooting in Pennsylvania in 2006 (it's an Adobe Acrobat file in .PDF format.  WARNING:  Autopsy photographs of the perpetrator are included.  NOT FOR THE SQUEAMISH!);
• 'Why one cop carries 145 rounds of ammo on the job'.  (Note that in the incident described, he carried 37 rounds of .45 ACP and 10 rounds of 9mm;  today, he carries more than three times that total, all 9mm.  It's not just a caliber or cartridge issue.  As the old saying reminds us, "quantity has a quality all its own".)

I've quoted Jim Higginbotham before.  He's an instructor with vast experience, and I highly respect his views.  Here's an excerpt from his article 'Triggernometry:  The “Center Mass” Myth and Ending a Gunfight'.

I have accumulated confirmed incidents in which people have been shot “center mass” up to 55 times with 9mm JHP ammunition (the subject was hit 106 times, but 55 of those hits were ruled by the coroner to be each lethal in and of themselves) before he went down. During training at the FBI Academy we were told of a case in which agents shot a bank robber 65 times with 9mm, .223 and 00 buckshot – he survived! These are not rare cases. The happen quite often.

. . .

I can find no real measure - referred to by some as a mathematical model - of stopping power or effectiveness. And I have looked for 44 years now! Generally speaking I do see that bigger holes (in the right place) are more effective than smaller holes but the easy answer to that is just to shoot your smaller gun more - "a big shot is just a little shot that kept shooting". True, I carry a .45 but that is because I am lazy and want to shoot less. A good bullet in 9mm in the right place (the spine!) will get the job done. If you hit the heart, 3 or 4 expanded 9mms will do about what a .45 expanding bullet will do or one might equal .45 ball . . . IF (note the big if) it penetrates. That is not based on any formula, it is based on what I have found to happen - sometimes real life does not make sense.

. . .

Circumstances in a real gunfight are unpredictable ... In real life, your gunfight may be dark, cold, rainy, etc. The subject may be anorexic (a lot of bad guys are not very healthy) or he may be obese (effective penetration and stopping power of your weapon). There are dozens of modifiers which change the circumstance, most not under your control. My only advice on this is what I learned from an old tanker: "Shoot until the target changes shape or catches fire!" Vertical to horizontal is a shape change, and putting that one more round into his chest at point blank range may catch his clothes on fire, even without using black powder.

We tell our military folks to be prepared to hit an enemy fighter from 3-7 times with 5.56 ball, traveling at over 3,000 feet per second. This approach sometimes worked, but I know of several cases where it has not, even "center mass".

With handguns, and with expanding bullets, it is even more unpredictable, but through years of study I have developed a general formula, subject to the above mentioned unpredictable circumstances.

• 2-3 hits with a .45;
• 4-6 with a .40;
• 5-8 with a 9mm.

There's more at the link.  Highly recommended reading.

So . . . where can we learn about general cartridge effectiveness in incapacitating our target?  The answer lies in the hunting field.  Generations of hunters have shot animals of all shapes, sizes and temperaments, and they've learned a great deal about how to do so efficiently, effectively and as humanely as possible.  Let's look at typical 'lessons learned' by hunters.

First, one should use a cartridge that's adequate for the game being hunted.  A common rule of thumb used by hunters of whitetail deer is that one needs a cartridge that can deliver at least 1,000 foot-pounds of energy at typical engagement ranges.  That doesn't mean that a cartridge delivering two, or three, or four times as much energy is not suitable - it's just not necessary under normal circumstances.  Why subject yourself to more blast and recoil than you have to?  (Note, too, that it's very common for game animals to run for up to a hundred yards, sometimes further, even when shot through the heart.  They're already dead - they just haven't figured it out yet.  That's why some hunters prefer to 'break down' the animal by shooting at the shoulders or major joints, so that it can't run, then finishing it off with a heart shot.)

For hunting dangerous game, the energy requirements climb;  but so do other needs.  A big Alaskan brown bear can weigh up to 1,000 pounds, have very heavy bones, and charge you at 35 miles per hour.  You'd better have a cartridge that can penetrate his skull and take out his brain, or smash through shoulder joints and immobilize him.  If you don't, he'll be the hunter and you'll be the victim.  It's happened many times before.  You don't want bullets that will use their kinetic energy to aid expansion - that's useless under such circumstances.  Penetration and bone-smashing power is everything.

For the largest African game like elephant, rhino or hippo, those requirements are even more imperative.  An elephant's brain is protected by a thickness of up to three feet of bone and cartilage in the center of its skull.  Sure, if you shoot from a distance, when he's not aware of your presence, you can slip a jacketed 7mm. or .30-caliber slug through the back of the neck.  ('Karamojo' Bell was famous for this.)  On the other hand, if he scents you and launches an all-out screaming charge, you've got to take him head-on through all that bone and cartilage, and put a bullet where it'll switch him off right then and there.  If you don't, they'll be taking you home in buckets, and at least half the weight will be mud - your blood mixed with African soil.  (I've seen that outcome with my own eyes.  It wasn't pretty and it didn't smell good.  The victim had a closed-coffin funeral - actually, a hermetically sealed coffin - with sandbags added to make up the weight we couldn't recover after the hyenas and jackals had done their work.  We didn't tell his family about that bit.)  To save your favorite butt, you need a really heavy, deep-penetrating bullet that won't waste any of its energy on expansion.  That's why most African dangerous game rifles are from .400" up to .600" in caliber, firing bullets in the 400-700 grain range.  Anything lighter just won't get the job done under such do-or-die circumstances.

Several formulas were evolved by various cognoscenti to try to quantify the penetrative attributes and assess the effectiveness of various cartridges against the dangerous game of that continent.  I've covered the most important ones in a previous article, which I suggest you read (and follow the links) for more information.  Modern ballistics buffs tend to scoff at them, claiming that their predictions don't square with scientific investigations and/or calculations.  However, old Africa hands just smile and carry right on using them . . . because they work in the field.  They test out when shooting actual animals who pose a deadly threat.  Make of that what you will.

The 'old-time' formula I most use is the Taylor KO or 'knock-out' factor.  (To illustrate what I mean about modern ballistics buffs and their scoffing, read this comment at the link I've just provided.  Someone's pointing out that in a totally unrealistic calculation, Taylor's KO value is meaningless.  Yes, in that calculation, it is - but that's a misuse of his formula.  In the real world, in African hunting, it just plain works.  Don't like that?  Too bad.  Those of us who know better, having seen it in action, will go right on using it.)

Using Taylor's KO calculations (see link), we find that a typical 9mm. bullet scores 7.31 while a typical .45 ACP bullet scores 12.3.  That's not far off what Jim Higginbotham postulates in his article cited above, is it?  (Note that the Taylor scores don't take the type of bullet into effect, or how much it may or may not expand.  Back in his day, there weren't any jacketed hollowpoints such as we use today.  He's calculating only the "shock power" of the bullet.)

Another factor I use in my assessment is bullet momentum.  Remember, scientifically speaking, energy is the capacity of a physical system to perform work.  Momentum is one factor in overall energy.  It's 'strength or force gained by motion'.  It's calculated by multiplying the object's mass by its velocity.  Thus, a heavy object moving slowly can have the same energy as a light object moving fast;  but in terms of typical handguns (not involving exotic rounds that aren't really suitable for defensive use), one can't propel a light bullet fast enough to make its momentum equal to a heavier, slower bullet.  I discussed bullet momentum in an earlier article;  please consult it for more information.

You can see these factors at work in modern handgun hunting ammunition.  Consider, for example, the outstanding Garrett cartridges in .44 Magnum.  The most powerful of them, a 330gr. hard-cast solid moving at 1,400 feet per second, provides muzzle energy of over a thousand foot-pounds from a 7½"-barrel handgun.

The manufacturer claims that "Full body-length penetration is the norm on all big game up to about 1000 pounds" - which would include moose, caribou and almost all species of bear in North America.  That's enormously impressive performance from a handgun, outperforming many rifle rounds in terms of momentum and penetration.  However, you'd be ill-advised to use it as a defensive cartridge against a human attacker, because it's more than capable of shooting right through him, and one or two other people behind him, and still retaining enough energy to penetrate a car or the wall of a house and kill someone inside.  If that someone is a mother or a baby, guess who's going to be crucified in the press and probably convicted in court?  That's right - you are.

On the other hand, a much less powerful cartridge such as Federal's 200gr. lead hollowpoint load in .44 Special can be fired in the same handgun as the .44 Magnum Hammerhead round.  It offers muzzle energy of only 336 foot-pounds, but adequate penetration and momentum for defensive use, and is much less likely to over-penetrate a human target.  One has to choose the load that's most appropriate under the circumstances.  The .44 Special load would be a foolish choice against an aggressive bear.  The Hammerhead load would be a foolish choice against a human attacker in an urban environment.

Note, too, how muzzle energy alone isn't always a good predictor of performance.  The Garrett Hammerhead's muzzle energy is roughly equivalent to that produced by military M855 ammunition (shown below) fired from an M4 carbine (the standard US Army rifle and ammunition).

However, the tiny 62gr. small-caliber rifle bullet would probably perform very poorly against a large Alaskan brown bear.  An entire magazine of 30 M855 bullets might bring him down . . . but again, it might not.  The Garret Hammerhead bullet, with its much greater diameter (.429" versus .224"), momentum (56 versus 26) and Taylor KO factor (24 versus 5), will offer incomparably superior performance against such an animal.

So, to cut a long story short, when one combines ballistic gelatin testing, plus the Taylor KO factor, plus bullet momentum, one gains (in my experience, at least) a pretty good understanding of how well a round is likely to perform in a defensive situation.  Unsurprisingly, it turns out that Jim Higginbotham's 'guesstimates' cited above are pretty much right on the mark.

However, those guesstimates aren't the only factor driving our selection of what gun and cartridge to carry.  In an earlier article covering the changing urban self-defense environment, I pointed out:

The odds of having to deal with multiple assailants are now much higher than in the past; therefore, it pays to select a handgun with a large magazine capacity. This, in turn, implies selecting a caliber that permits such a capacity. A bigger cartridge such as the .45 ACP may be very effective, but it's too large to permit the same handgun magazine capacity as a smaller cartridge such as the 9mm. Parabellum. With modern high-performance ammunition (my preference in the latter cartridge is currently Winchester's RA9TA) the smaller round now develops 80%-90% of the energy of the larger round, and has proven almost as effective in actual shooting incidents. I submit that for the average shooter (not necessarily for highly-trained experts), giving up 10%-20% of bullet energy in exchange for greatly increasing a handgun's magazine capacity may be a worthwhile trade-off.

There's more at the link.

This means that even though the 9mm. round may be less effective overall, by the criteria I've outlined above, than a .45 ACP round, I can carry a lot more of the former than I can of the latter.  Provided I put a 9mm. round in the right place, I can trust it (in its modern incarnations) to do an effective job;  and although it won't deliver the same 'KO factor' or momentum as a .45 ACP bullet, it will deliver enough to do the job, provided it hits a vital zone.  I have to accept the 'penalty' of shooting straight, putting each round where it will be most effective, if I want to make the most of the 9mm.  If I don't - if I 'spray and pray', as the old saw goes - I'm unlikely to find it very effective.

Therefore, when I'm going into situations or environments where multiple targets are a possibility, I carry a 9mm. pistol with at least two spare magazines, giving me 40-50 rounds on hand.  If a situation is tense (for example, the recent 'Black Lives Matter' protests in various cities), I'll carry additional spare magazines.  When I'm going about my normal business in and around my home, or in more relaxed areas of town, I'll carry a .45 ACP pistol with fewer rounds, because I'm less likely to need a lot of them, and I'd like to take advantage of the proven performance of the heavier round if necessary.  A .45 pistol equipped with a light rests beside my bed at night for the same reason.

Note, too, the third example from the real world that I provided above.  Sergeant Gramins only just managed to stop his attacker after expending no less than 33 rounds of .45 ACP.  That's why he now carries 145 rounds of 9mm. when on duty.  He doubtless accepts that the smaller round will be less effective, bullet for bullet, than the heavier one;  but I'm sure he feels a lot more comfortable with the larger quantity of ammunition he now has on hand.  That's precisely the same argument I make in favor of the 9mm. in environments where multiple attackers are more likely.  Those factors, plus others (including the greater ease of control of the lighter round), are why the FBI recently announced it was reverting to 9mm. as its duty round, after years of issuing handguns chambered in .40 S&W to its agents.  (Of course, FBI agents usually have access to higher-performance shotguns and rifles as well as their handguns when they're on duty, particularly if they're expecting trouble.  The average armed citizen, carrying concealed, does not.)

So, when selecting a defensive cartridge and bullet for yourself, I suggest you follow the steps outlined above.

1. Work out your personal priorities.  These can vary considerably.  If money is tight, you need to select a round that you can afford to buy in larger quantities for training and practice purposes (essential to prepare yourself for the 'real thing'), as well as a couple of boxes of more effective defensive ammunition.  (This is where, for example, 9mm. scores heavily over .45 - it's much more affordable in quantity.)  On the other hand, if you need a more powerful round for dual-purpose use (e.g. defense against human assailants and medium-size problem animals, such as you'll find on farms or in rough country in various parts of the USA - wolves, black bear, hogs, etc. come to mind - or packs of feral dogs that are found in some localities), then something like the .45 ACP cartridge may be more appropriate.  There are many factors that will affect each individual's choice.
2. Having chosen the cartridge, examine the available defensive rounds for it, using ballistics tests and information such as that provided in the discussion cited above.  At the same time, analyze the options and choices available to you in terms of Taylor's KO factor and bullet momentum.  Select an effective round in terms of modern testing that also scores as high as possible against both of the older measures.  That should be your primary choice for defensive ammunition.
3. I strongly recommend selecting a cartridge that can handle your worst possible problem in your environment.  If you live in a city with no real animal problems, but a crime problem, a smaller cartridge may be adequate for your needs.  If animals are also a problem (for example, feral dogs can be very tough to put down, and if there's a pack of them you can't afford to put half a dozen lighter rounds into each animal - the others will get you while you do that), you probably need a heavier cartridge.  A round that can handle the latter problem will also deal with the former problem quite adequately, but not necessarily vice versa.

I hope this discussion has clarified the situation somewhat.  It's a very complex area, with partisans arguing for their own perspective and against everyone else's on all sides of the debate.  I'm old-school.  I go with what's been proven to work 'on the street' or 'in the bush' as much as I do the results of modern scientific investigation.  I reckon by putting both sides together, I get the best of both worlds.  Your mileage may vary, of course.

In closing, let me quote Sergeant Timothy Gramins, whose lethal force encounter I cited above as an example of bullet performance.  He doesn't mince his words.  From the sidebar of that article:

“When you fire multiple ‘lethal’ rounds into an attacker and he keeps going, you don’t have the luxury of waiting 20 or 40 more seconds for him to die while he can still shoot at you. Don’t waste time arguing the relative merits of various calibers. No handgun rounds have reliable stopping power with body shots. Pick the round you can shoot best and practice shooting at the suspect’s head.”

I can't help but agree.

Peter