Does the Ever-Popular 9mm Luger Offer Effective Stopping Power?

By: Warren Gray

“God is not on the side of the big battalions,
but on the side of those who shoot best.”
— Voltaire (French writer and philosopher),

Let’s face it, none of us really wants to have to shoot someone, but there’s a popular country music song by Billy Currington that goes like this: “God is great, beer is good, and people are crazy.” And, every now and then, one of those crazy people tries to rob or assault someone at gunpoint.

Hopefully, if something like this ever happens to you, you’ll have your concealed carry permit (if allowed) and a decent pistol handy. Approximately 92 percent of the time, whenever a law-abiding citizen draws his or her weapon, the felon immediately leaves the scene without a shot being fired.

But let’s say that your assailant either doesn’t see your gun or simply doesn’t care. In that case, you must take action. The most common caliber for self-defense pistols is currently 9mm Luger, which is large enough to be reasonably effective, and small enough that the recoil isn’t a major problem. It’s also the standard pistol caliber of the U.S. Armed Forces, in very widespread use.

According to police and FBI statistics, the average civilian shooting incident takes place at approximately 10:40 p.m. at night, with fairly poor visibility, at a nominal range of about seven feet. Four shots are typically fired within the span of five seconds, and incredibly, three of them miss completely! You’ll get tunnel vision, time will seem to slow down dramatically, and those five seconds will feel more like five long minutes.

As a graduate of a professional shooting school, I took some useful notes on how to be the person who does not miss: Use two hands whenever possible, keep a relaxed grip, apply constant, even pressure on the trigger, let it surprise you when it goes off, and if you can’t remember anything else, remember this: Front sight, front sight, front sight! Keep it in focus, if you can in the dark (a white dot on the sight really helps), and let the rear sight and target blur slightly. The bullet will go where the front sight is aiming, every time.

We can all hope that it never happens to us, but statistics prove that ordinary citizens with lawfully possessed firearms shoot nearly five times as many felons each year as police do, simply because the police cannot be everywhere at once. So, assuming that it does happen to you, and you manage to get that one, solid hit on the perpetrator, how likely is it to stop his (or sometimes, her) belligerent actions with just one shot?

The relative stopping power (RSP) of any bullet is determined by a simple formula: Velocity x Weight x Cross-sectional area x Shape factor x Hydrostatic-shock effect (or V x W x C x S x H), all divided by 1,000, to get rid of the excess zeros. The minimum desired RSP is 20, with a desired velocity of at least 1,200 feet per second (Mach 1.06, supersonic), a desired, kinetic energy of at least 400 foot-pounds (the ability to shove a 200-pound assailant back two feet, literally knocking him off-balance), a desired, bullet expansion of .70” (twice its original diameter for a 9mm) or better, a desired penetration of approximately 12 to 13 inches, and a desired, one-shot stopping record of at least 85 percent. These are fairly tough standards to meet.

Then, we get into the whole controversy regarding which bullet weight is best. Some prefer the lightweight, high-velocity rounds, while others prefer the slower, heavier rounds that supposedly penetrate deeper. Too much penetration, however, can be a bad thing, passing through the felon and possibly hitting innocent bystanders, resulting in likely lawsuits and possible prison time. And an over-penetrating bullet does not expend all its energy inside the target, thereby reducing its effective stopping power.

The average human torso is only 9.4 inches from front to back (I’m 6’2” tall, 183 lbs., and my chest is 9.8 inches deep), and even from an angled shot, the heart and lungs are only about eight inches deep, and the maximum chest width is about 16 inches. So, while the FBI prefers 12 to 18 inches of penetration, a safer, more-realistic, effective depth is 10 to 15 inches. Even a mere nine inches will usually do the job effectively enough, according to the FBI, but more than 15 inches is simply too much.

With all of this background information in mind, let’s take a look at the terminal effects of five, well-known, available, hollow-point, self-defense loads in a variety of bullet weights, ranging from 95 grains to 150 grains:

Barnes TAC-XPD +P, 115-grain, solid-copper hollowpoint (SCHP.)
CorBon DPX, 95-grain SCHP.
Defender Ammunition, 124-grain, jacked hollowpoint (JHP.)
Federal HST Micro, 150-grain JHP.
Norma MHP, 108-grain SCHP.

Most of these loads have already been tested in ballistic gelatin, so we have an idea of what to expect in terms of velocity, weight, energy, penetration, expansion, and RSP, but most ordinary citizens aren’t going to use a chronograph to measure muzzle velocity, or ballistic gelatin to examine the terminal effects of bullets. What is commonly available, however, and quite inexpensive, is wet, modeling clay from a craft store.

My youngest son is now a county police officer (the oldest is an Air Force pilot), and I worked for the FBI for three years, and later had some military, special operations experience, including the professional shooting school. In 2004, my police son and I carefully tested a number of different types of ammunition in clay blocks for one of his college courses on Criminal Investigation, and he wrote an 11-page term paper on the process and gave a PowerPoint presentation, receiving an “A” grade for the project.

Wet, natural clay is generally similar in consistency to ballistic gelatin, but not clear, not nearly as elastic, and a bit denser. Still, it can provide a reasonably accurate measurement of bullet penetration and expansion and is certainly useful for comparing one load against another to see how they stack up under actual shooting conditions.

But if we already have data from terminal effects testing in ballistic gelatin, why bother with very messy, clay testing? In a word: consistency. It’s exceptionally worthwhile to test these five different loads under carefully controlled, identical conditions: the same shooter, same pistol, same barrel length, same test medium (blocks of clay), same weather conditions, same day, and so on, to remove as many variables as possible. Also, clay-block testing allows us to accurately measure the temporary wound cavity, which is the stretch cavity caused by hydrostatic-shock effect as the hollowpoint bullet mushrooms inside the clay.

I tested them from a small, concealable, Ruger LC9s Pro pistol, with a 3.12-inch barrel. All of these cartridges have an RSP rating of about 16.7 to 18.6, at least on paper, so even these fine 9mm loads are not quite within the minimum, desired range for a one-shot stop against an armed assailant. The very best 9mm rounds only reach the demonstrated, 83-percent level for one-shot stops, which is still below the desired standard. Likewise, only one of them reached or exceeded the desired, 1,200 fps muzzle velocity from this very short barrel, and only that same one even came close to the desired, kinetic-energy level, while not quite reaching it.

What all of this means is that under the stress of the shooting incident, you’re probably only going to land one clean shot on the perpetrator, and a 9mm round is really marginal for dropping him instantaneously. There’s an old saying: “Make sure you bring enough gun.” Usually, a .40 S&W or .45 ACP firearm qualifies as “enough gun.”

I own a .45-caliber Glock, but it’s much bulkier and harder to conceal than my slim, streamlined Ruger, so chances are the 9mm will be my primary weapon in demanding circumstances like this, and I’d better make the most of it. Solid shot placement is my best bet, but it’ll likely be dark, confusing, and certainly very noisy once the shooting starts, and shot placement becomes uncertain. I’ll be lucky just to hit the felon at all. That leaves bullet design as the deciding factor, assuming that I’m the one who actually hits my target. Are any of these five rounds noticeably better than the other?

All terminal-effects testing was accomplished near Knoxville, Maryland, 465 feet above sea level, on Wednesday, September 4, 2019, with an ambient air temperature of 85 degrees, using digital calipers to measure bullet expansion. Here are the candidates:

Barnes TAC-XPD +P, 115-grain SCHP: This is a standard-weight (for a hollowpoint), solid-copper round, rated at fairly-mild, +P pressure, although its muzzle velocity is quite modest, at only 1,043 fps from this small handgun. It has a nickel-plated casing to help ensure smoother feeding into the gun’s chamber, and the copper bullet itself is coated with black nickel for a distinctive appearance. Barnes only makes all-copper projectiles, which tend to retain all of their weight during rapid expansion, usually without fragmenting, as was proven by the testing.

In 2015, the TAC-XPD, from a 3.5-inch barrel, yielded a muzzle velocity of 1,043 fps, penetrated 13.4 inches, and expanded to .70-caliber in ballistic gelatin. CorBon’s very similar, 115-grain DPX load produced almost identical results, being 80 fps faster and penetrating only a half-inch deeper, but was otherwise the same.

Actual, clay-block, test results: Temporary cavity = 3.2 inches wide, penetration = 12.3 inches deep, and bullet expansion = .707-caliber. Penetration and expansion are ideal, and the wound cavity was impressive enough, and nine inches long.

CorBon DPX, 95-grain SCHP: This was the lightweight, high-speed entry of the group, also made in 115 grains, but tested for comparison purposes to see how well this lighter bullet penetrates. It’s another SCHP design, with a bare-copper, Barnes bullet in a standard, brass casing. CorBon is a well-known, proven brand, based in Sturgis, South Dakota, with a demonstrated, track record of producing high-quality, high-performance ammunition. The usual advantages of very lightweight bullets are reduced recoil for the shooter, and reduced penetration, when overpenetration is a real concern.

This load was specifically designed by the manufacturer to reach a blazing, muzzle velocity of 1,300 fps (Mach 1.15, supersonic) from a short, 3.1-inch barrel, with 356 foot-pounds of energy, at least 12 to 13 inches of penetration (which is ideal), and it typically expands to about .61-caliber, which is a respectable, 1.7 times its original diameter (1.5 times is usually considered very good), but it still didn’t reach the desired expansion level of .70-caliber.

Actual, clay-block, test results: Temporary cavity = 3.75 inches wide, penetration = 15.2 inches deep, and bullet expansion = .373-caliber base. The bullet fragmented, shedding all six of its hollowpoint petals in its passage, and the base surprisingly penetrated much deeper than expected for such a lightweight projectile. I’d actually worry about overpenetration with this super-fast load.

Defender Ammunition, 124-grain JHP: The most-conventional load of the group, at a standard, 9mm bullet weight for a lead bullet, although slightly heavy for a hollowpoint design. This is a normal, jacketed hollowpoint, the least expensive of the group, but it has an interesting, grooved, nose-cavity design that caught my attention. The Defender Ammunition Company is a veteran-owned organization, based in Raeford, North Carolina, only about twenty miles from Fort Bragg, where I had my unique, special operations assignment. So, their ammo is designed and built by former paratroopers and Special Forces soldiers, many of them with combat experience in Afghanistan or Iraq.

I found an online ballistic-gelatin test for this round, which achieved a nominal muzzle velocity of 1,060 fps from a 4-inch barrel, penetrated 12.3 inches (also ideal), and expanded to .72-caliber on average, so we know generally what to expect from the Defender load, at least from a longer barrel length.

Actual, clay-block, test results: Temporary cavity = 4.4 inches wide, penetration = 16.5 inches deep, and bullet expansion = .765-caliber. The bullet was badly mangled, and only expanded at a 45-degree angle by accident, so this amount of expansion cannot be consistently relied upon, and the temporary cavity was enormous, but overpenetration is a real concern with this load.

Federal HST Micro, 150-grain JHP: This is the slow, heavy round for deeper penetration, specifically designed for very compact, short-barrel pistols like the Ruger LC9s Pro. There’s a nickel-plated casing and a copper-jacketed, lead bullet, a fairly conventional design, but HSTs are known to expand well, due to their soft, lead composition, and the clay testing proved this to be correct.

While there is a growing trend toward heavier, 147-grain bullets in this caliber, it’s important to remember that this particular weight was originally designed for U.S. Navy SEALs, not to make the bullet more effective or better-penetrating, but simply to slow it down to subsonic velocities for firing from an MP5SD3 suppressed, submachine gun, to make both the weapon and the ammunition as quiet as possible.

But as soon as the public heard that the Navy SEALs were using 147-grain bullets, there was a widespread assumption that the rounds must be better manstoppers, which was really not the case at all. In actual fact, these heavy bullets are prone to overpenetration and poorer expansion than lighter bullets. But Federal claims that this 150-grain, HST bullet expands quite well, and doesn’t penetrate quite as deeply as most of the other heavy loads. That’s a tough standard to meet.

This is also the most politically correct and non-controversial of the tested loads, because a majority of U.S. police departments use high-quality, Federal HST ammunition, so it’s considered “police-approved.” In today’s violently anti-gun climate, legal firearms owners are often considered guilty until proven innocent in any shooting incident, and if you ever have to shoot anyone, there likely will be a court trial, with your every action, and even your ammo choice, closely scrutinized. Using accepted, “police” ammo definitely works in your favor under such difficult circumstances, and this was the load that I had carried in my primary, LC9s magazine before this testing began.

This round was also tested in clear, ballistic gelatin in 2015, when it achieved a leisurely, muzzle velocity of 888 fps, penetrated to 17.3 inches (too much, by any standard), and expanded to .71-caliber.

Actual, clay-block, test results: Temporary cavity = 3.5 inches wide, penetration = 11.9 inches deep, and bullet expansion = .711-caliber. The bullet expanded exactly as anticipated, and its actual penetration was less than expected, but still within ideal parameters for rapid incapacitation. In gelatin, however, penetration was excessive.

Norma MHP, 108-grain SCHP: This is a brand-new entry as of 2019, advertised as “The most-expanding, 9mm bullet in the world.” It’s a solid-copper bullet (MHP stands for “Monolithic Hollow Point”), with a very small, visible cavity at the nose, which peels back quite a bit into four large petals, like a copper flower, expanding quite dramatically. Designed in Sweden, the brass casing is dark gray (black-oxide coating), with a shiny, nickel-plated bullet, and they’re actually made in Hungary.

This reminds me of a humorous, gun-related anecdote: While traveling in Hungary in 2000 to perform a series of military presentations, I was having pheasant for dinner on the terrace of the Betekints Hotel in Veszprém, at the edge of town, with the Séd River and some wooded wetlands nearby. Another officer ordered duck soup, bit into a piece of the tasty meat, and extracted a round piece of #4 lead bird shot. “Well,” I remarked with a smile, “we definitely know its’s fresh!” Hungary’s manufacturing industry is very modern today, but sometimes the good, old-fashioned ways are best.

Shooting Illustrated magazine tested the new, Norma MHP load in ballistic gelatin in early August 2019 from a very-short-barrel, SIG P365 pistol, and achieved a muzzle velocity of 1,031 fps, an energy of 255 ft./lbs., penetration of 10.5 inches, and incredibly impressive expansion out to .888-caliber!

Actual, clay-block, test results: Temporary cavity = 4.0 inches wide, penetration = 9.5 inches deep (10.5 inches in ballistic gelatin), and bullet expansion = .937-caliber! Wow!!! This bullet certainly lived up to the manufacturer’s claim as “the most-expanding, 9mm bullet in the world.” It’s definitely not hype. Penetration was less than any of the other tested rounds, but quite adequate for hitting vital organs from almost any angle, and its spectacular, temporary wound cavity was about the size of both of my fists (from the wrist bones forward) touching each other. Truly impressive!

In conclusion, they were all decent, reliable loads, but in a confrontational scenario, where you must decisively stop an armed assailant with just one shot from a 9mm pistol, literally trusting your life to that single bullet, without overpenetrating and hitting an innocent bystander, the new, Norma MHP round stands out as a clearly decisive fight-stopper. Its penetration depth of 9.5 to 10.5 inches meets the desired level and is more than compensated for by its devastating expansion and permanent wound cavity, drilling a ragged hole nearly an inch wide by 10 inches deep into your assailant.

The more-traditional Barnes TAC-XPD penetrates slightly deeper, and performs very consistently, making it my second choice (in my spare magazine) among the five tested. The clay-block tests proved that the very light and very heavy loads were less consistent and reliable than the “standard,” hollowpoint, design weights of 108 to 115 grains. So, if one solid hit on a dark night is all you get for self-defense on average, then I’ll trust my life to the Norma MHP or Barnes TAC-XPD every time, because now I know exactly how they’ll perform.

Warren Gray is a retired, U.S. Air Force intelligence officer with experience in joint special operations and counterterrorism and is an NRA member. He served in Europe and the Middle East, earned Air Force and Navy parachutist wings, four college degrees, and was a distinguished graduate of the Air Force Intelligence Operations Specialist Course, and the USAF Combat Targeting School. He is currently a published author and historian. You may visit his web site at:


Disclaimer: The views expressed in this article are those of the author and do not necessarily reflect those of Gunpowder Magazine.