The 9mm Parabellum (aka 9mm Luger) is currently the most popular sidearm caliber for both military and law enforcement, as well as civilian use. I believe the first significantly large police force to officially adopt a 9mm was the Illinois State Police Department in 1967. Throughout the ‘70s and early ‘80s, most police departments chose to stay with the time-tested revolver.
Then something happened that would have far-reaching effects for every police agency in the United States in how they viewed weaponry, training, and tactics. It happened on April 11, 1986, and it became known as the 1986 FBI Miami-Dade Shootout. At that time very few police departments had transitioned to 9mm autos, with most still using .38 Special/.357 magnum revolvers. The shootout involved two criminals, William Matix and Michael Platt, and eight FBI agents. Matix and Platt had already murdered several people and robbed several banks and armored carriers. The FBI agents were part of a task force created to apprehend them. A lot went wrong that day and when the shooting was over both criminals and two Special Agents, Jerry Dove and Benjamin Grogan, lay dead. Five of the remaining six agents were seriously wounded.
This is one of the most analyzed events in law enforcement history. One undeniable fact is that the FBI agents were seriously outgunned by the fact that Platt was armed with a semi-automatic Ruger Mini14 rifle with high-capacity magazines. Five of the agents were carrying revolvers and three were carrying 9mm autos. Two of the agents were also carrying backup .38 Special revolvers, and both would see use during the encounter. I will summarize the details pursuant to our subject matter, but I encourage you to read some of the many detailed accounts of the approximately 4-minute-long engagement.
Both criminals were wounded very early on in the fight. Matix was shot in the head and temporarily lost consciousness. Platt was struck by a 9mm bullet that penetrated his upper right arm, missing the bone but severing the brachial artery. It then entered the right upper chest, collapsed the right lung, and came to a stop just short of the heart. The autopsy showed that this wound was fatal. After he was fatally wounded, Platt managed to live for more than three more minutes, during which time he took the lives of Dove and Grogan. By the time it was over, Platt had been shot 12 times and Matix 6. Platt inflicted all of the wounds to the 7 agents. Matix apparently never fired a gun prior to being put out of action with the head shot, though he regained consciousness.
In the ensuing investigation much emphasis was given to two things that seemed quite obvious to authorities: the failure of the 9mm Luger 115 grain Winchester Silvertip hollowpoint bullet to stop an assailant in a timely manner and the relatively slow and difficult process of reloading a revolver (compared to a semi-auto) were both significant factors in the deaths of agents Dove and Grogan.
During the following three years the FBI launched an extensive testing program to find a replacement for the 9mm Winchester load they issued at that time. Along with various 9mm offerings, they tested loads in the .45 ACP and the new 10mm Auto cartridge. The 10mm seemed to be closest to achieving the performance levels they were looking for, but its recoil proved to be too excessive. They asked for a reduced 10mm load and decided that the performance of this new offering satisfied their criteria. Smith & Wesson used their Model 4506 auto chambered in .45 ACP to develop a handgun around the reduced 10mm load. The reduced powder charge resulted in a substantial amount of air space in the case. Smith & Wesson found that the same performance level could be achieved in a shortened 10mm case, and it would also result in a cartridge that could fit into current duty-sized 9mm handguns. Collaborating with Winchester, they developed the new cartridge, dubbing it the .40 Smith & Wesson.
The .40 hit the market in 1990. During this period of development the number of police agencies using the 9mm in a semi-automatic handgun had increased, but many still used the revolver. Law enforcement agencies and civilians alike took notice of the FBI’s testing protocols and resultant adoption of the .40 S&W cartridge. Now when departments decided to switch to the auto, they had a choice between the 9mm, the .40 S&W, and the venerable .45 ACP.
Few cartridges have become popular as quickly as the .40. The number of agencies using it grew exponentially, and the civilian market followed suit. Many agencies that had transitioned from the revolver to the 9 now transitioned over to the .40. Some agencies that had not yet adopted the auto went straight to the .40. It became available in nearly as many makes and models as the 9mm, save for the smallest ones. On average, the .40 develops more energy than either the 9mm or .45 ACP. Of course this results in somewhat greater muzzle blast and recoil. Also, in the same size magazine the .40 usually holds one to three cartridges less than the 9, but still one to three more than the fat .45 cartridge.
In the middle of all this transitioning going on, one more option was thrown into the mix in 1994. It was the result of a collaboration between firearm manufacturer SIGARMS (they have since changed back to their former name of Sig Sauer) and ammunition manufacturer Federal. Sig decided to name it the .357 Sig. The old .357 Magnum revolver cartridge, loaded with a well-designed 125 grain jacketed hollowpoint bullet, had long been the standard by which all other defensive loadings were compared. It had a well-deserved “street reputation” among law enforcement for its ability to stop a threat. I believe that it was a calculated move on Sig’s part to use “.357” in the new cartridge’s name. It would have been far less confusing to the less sophisticated of the shooting fraternity if they had named it something more accurately descriptive, like “9mm Magnum”, but they were actually playing to that slight confusion. They wanted to form a connection to the highly respected magnum cartridge. The new Sig had no more in common with the .357 Magnum revolver cartridge than it did with any other. It uses a .355 inch bullet like the .380 and 9mm. The .357 Magnum and .38 Special use a .357 inch bullet. The magnum is a rimmed cartridge designed for revolvers. The Sig is a rimless cartridge designed for autos. The Sig is also a bottle-necked cartridge, while the magnum uses a straight-walled case. Actually, the two could hardly be more different.
By 1994 most law enforcement agencies had transitioned to the auto but, if their department let them, some old timers still clung to their .357 wheel guns, as well as did a few entire police agencies. They had learned to depend on it, and were reluctant to replace it with something that they felt was less proven. Sig was (and is) heavily involved in the competition to arm our law enforcement agencies as well as the military, and were certainly aware of this yet untapped market still hanging onto the venerable .357 revolver.
The goal of Sig was to equal the performance of the big magnum’s popular 125 grain JHP load. Using a 125 grain bullet, the Sig did just that. In fact, most factory loads available in that bullet weight or lighter will surpass (some quite significantly) the big magnum in similar barrel lengths. If, for whatever reason (such as hunting), one desires a substantially heavier bullet, then the magnum will begin to pull away from the Sig. The Sig is loaded to greater pressure than the magnum, but it has far less case capacity to make room for powder and bullet. For defensive use, I see this as having no consequence. There are many deep-penetrating loads available for the Sig with 125 grain and lighter bullets. The Sig is also more comfortable to shoot than a full-throttle .357 Magnum load in a small to medium frame revolver.
The .357 Sig never became anywhere near as popular with law enforcement agencies as the .40, or even the 9. But many did opt for its use, including the Secret Service and other federal agencies. It became second only to the .40 with state law enforcement agencies, beating out both the 9 and .45.
When the .357 Sig was announced in 1994, I was immediately enamored with the ballistics of the new round. I currently own three .357 Sigs: a Kel-Tec P40, a Sig P250, and a Glock G27 Gen 4. All of these were .40 Smith & Wessons that I converted to the Sig round. When I carry (which is nearly always if I can legally do so), I’m usually carrying one of my .357 Sigs.
In the last several years we’ve come full-circle. Many agencies, at every level, who had transitioned from the 9 to the .40 or .357 Sig have returned to the 9. This all began when the agency that started it all, namely the FBI, decided to return to the 9 in 2014. That was 28 years after the shootout that precipitated the original transition away from the 9. Following is the FBI’s release of their justification for returning to the 9mm cartridge.
FBI Training Division: FBI Academy, Quantico, VA
Executive Summary of Justification for Law Enforcement Partners
Original Title:
Executive Summary of Justification for Law Enforcement Partners
Description:
FBI 9MM Justification, FBI Training Division , Justification for Law Enforcement Partners. May 6, 2014.
Caliber debates have existed in law enforcement for decades
- Most of what is “common knowledge” with ammunition and its effects on the human target are rooted in myth and folklore
- Projectiles are what ultimately wound our adversaries and the projectile needs to be the basis for the discussion on what “caliber” is best
- In all the major law enforcement calibers there exist projectiles which have a high likelihood of failing LEO’s in a shooting incident and there are projectiles which have a high incident likelihood of succeeding for LEOs in a shooting incident
- Handgun stopping power is simply a myth
- The single most important factor in effectively wounding a human target is to have penetration to a scientifically valid depth (FBI uses 12” – 18”)
- LEOs miss between 70 – 80 percent of the shots fired during a shooting incident
Contemporary projectiles (since 2007) have dramatically increased the terminal effectiveness of many premium line law enforcement projectiles (emphasis on the 9mm Luger offerings)
- 9mm Luger now offers select projectiles which are, under identical testing conditions, outperforming most of the premium line .40 S&W and .45 Auto projectiles tested by the FBI
- 9mm Luger offers higher magazine capacities, less recoil, lower cost (both in ammunition and wear on the weapons) and higher functional reliability rates (in FBI weapons)
- The majority of FBI shooters are both FASTER in shot strings fired and more ACCURATE with shooting a 9mm Luger vs shooting a .40 S&W (similar sized weapons)
There is little to no noticeable difference in the wound tracks between premium line law enforcement projectiles from 9mm Luger through the .45 Auto
- Given contemporary bullet construction, LEO’s can field (with proper bullet selection) 9mm Lugers with all of the terminal performance potential of any other law enforcement pistol caliber with none of the disadvantages present with the “larger” calibers
Justification for Law Enforcement Partners
Rarely in law enforcement does a topic stir a more passionate debate than the choice of handgun caliber made by a law enforcement organization. Many voice their opinions by repeating the old adage “bigger is better” while others have “heard of this one time” where a smaller caliber failed and a larger caliber “would have performed much better.” Some even subscribe to the belief that a caliber exists which will provide a “one shot stop.” It has been stated, “Decisions on ammunition selection are particularly difficult because many of the pertinent issues related to handguns and ammunition are firmly rooted in myth and folklore.” This still holds as true today as it did when originally stated 20 years ago.
Caliber, when considered alone, brings about a unique set of factors to consider such as magazine capacity for a given weapon size, ammunition availability, felt recoil, weight and cost. What is rarely discussed, but most relevant to the caliber debate is what projectile is being considered for use and its terminal performance potential.
One should never debate on a gun make or caliber alone. The projectile is what wounds and ultimately this is where the debate/discussion should focus. In each of the three most common law enforcement handgun calibers (9mm Luger, .40 Smith & Wesson and .45 AUTO) there are projectiles which have a high likelihood of failing law enforcement officers and in each of these three calibers there are projectiles which have a high likelihood of succeeding for law enforcement officers during a shooting incident. The choice of a service projectile must undergo intense scrutiny and scientific evaluation in order to select the best available option.
Understanding Handgun Caliber Terminal Ballistic Realities
Many so called “studies” have been performed and many analyses of statistical data have been undertaken regarding this issue. Studies simply involving shooting deaths are irrelevant since the goal of law enforcement is to stop a threat during a deadly force encounter as quickly as possible. Whether or not death occurs is of no consequence as long as the threat of death or serious injury to law enforcement personnel and innocent third parties is eliminated.
“The concept of immediate incapacitation is the only goal of any law enforcement shooting and is the underlying rationale for decisions regarding weapons, ammunition, calibers and training.”
Studies of “stopping power” are irrelevant because no one has ever been able to define how much power, force, or kinetic energy, in and of itself, is required to effectively stop a violent and determined adversary quickly, and even the largest of handgun calibers are not capable of delivering such force. Handgun stopping power is simply a myth. Studies of so called “one shot stops” being used as a tool to define the effectiveness of one handgun cartridge, as opposed to another, are irrelevant due to the inability to account for psychological influences and due to the lack of reporting specific shot placement.
In short, extensive studies have been done over the years to “prove” a certain cartridge is better than another by using grossly flawed methodology and or bias as a precursor to manipulating statistics. In order to have a meaningful understanding of handgun terminal ballistics, one must only deal with facts that are not in dispute within the medical community, i.e. medical realities, and those which are also generally accepted within law enforcement, i.e. tactical realities.
Medical Realities
Shots to the Central Nervous System (CNS) at the level of the cervical spine (neck) or above, are the only means to reliably cause immediate incapacitation. In this case, any of the calibers commonly used in law enforcement, regardless of expansion, would suffice for obvious reasons. Other than shots to the CNS, the most reliable means for affecting rapid incapacitation is by placing shots to large vital organs thus causing rapid blood loss. Simply stated, shot placement is the most critical component to achieving either method of incapacitation.
Wounding factors between rifle and handgun projectiles differ greatly due to the dramatic differences in velocity, which will be discussed in more detail herein. The wounding factors, in order of importance, are as follows:
- Penetration:
A projectile must penetrate deeply enough into the body to reach the large vital organs, namely heart, lungs, aorta, vena cava and to a lesser extent liver and spleen, in order to cause rapid blood loss. It has long been established by expert medical professionals, experienced in evaluating gunshot wounds, that this equates to a range of penetration of 12-18 inches, depending on the size of the individual and the angle of the bullet path (e.g., through arm, shoulder, etc.). With modern properly designed, expanding handgun bullets, this objective is realized, albeit more consistently with some law enforcement projectiles than others.
- Permanent Cavity:
The extent to which a projectile expands determines the diameter of the permanent cavity which, simply put, is that tissue which is in direct contact with the projectile and is therefore destroyed. Coupled with the distance of the path of the projectile (penetration), the total permanent cavity is realized. Due to the elastic nature of most human tissue and the low velocity of handgun projectiles relative to rifle projectiles, it has long been established by medical professionals, experienced in evaluating gunshot wounds, that the damage along a wound path visible at autopsy or during surgery cannot be distinguished between the common handgun calibers used in law enforcement. That is to say an operating room surgeon or Medical Examiner cannot distinguish the difference between wounds caused by .35 to .45 caliber projectiles.
- Temporary Cavity:
The temporary cavity is caused by tissue being stretched away from the permanent cavity. If the temporary cavity is produced rapidly enough in elastic tissues, the tensile strength of the tissue can be exceeded resulting in tearing of the tissue. This effect is seen with very high velocity projectiles such as in rifle calibers, but is not seen with handgun calibers. For the temporary cavity of most handgun projectiles to have an effect on wounding, the velocity of the projectile needs to exceed roughly 2,000 fps. At the lower velocities of handgun rounds, the temporary cavity is not produced with sufficient velocity to have any wounding effect; therefore any difference in temporary cavity noted between handgun calibers is irrelevant. “In order to cause significant injuries to a structure, a pistol bullet must strike that structure directly.” DiMaio, V.J.M.: Gunshot Wounds, Elsevier Science Publishing Company, New York, NY, 1987, page 42.
- Fragmentation:
Fragmentation can be defined as “projectile pieces or secondary fragments of bone which are impelled outward from the permanent cavity and may sever muscle tissues, blood vessels, etc., apart from the permanent cavity”. 3 Fragmentation does not reliably occur in soft tissue handgun wounds due to the low velocities of handgun bullets. When fragmentation does occur, fragments are usually found within one centimeter (.39”) of the permanent cavity. 4 Due to the fact that most modern premium law enforcement ammunition now commonly uses bonded projectiles (copper jacket bonded to lead core), the likelihood of fragmentation is very low. For these reasons, wounding effects secondary to any handgun caliber bullet fragmentation are considered inconsequential. 3 Fackler, M.L., Malinowski, J.A.: “The Wound Profile: A Visual Method for Quantifying Gunshot Wound Components”, Journal of Trauma 25: 522?529, 1958. 4 Handgun Wounding Factors and Effectiveness: Firearms Training Unit, Ballistic Research Facility, 1989.
Psychology
Any discussion of stopping armed adversaries with a handgun has to include the psychological state of the adversary. Psychological factors are probably the most important relative to achieving rapid incapacitation from a gunshot wound to the torso. 5 First and foremost, the psychological effects of being shot can never be counted on to stop an individual from continuing conscious voluntary action. Those who do stop commonly do so because they decide to, not because they have to.
The effects of pain are often delayed due to survival patterns secondary to “fight or flight” reactions within the body, drug/alcohol influences and in the case of extreme anger or aggression, pain can simply be ignored. Those subjects who decide to stop immediately after being shot in the torso do so commonly because they know they have been shot and are afraid of injury or death, regardless of caliber, velocity, or bullet design. It should also be noted that psychological factors can be a leading cause of incapacitation failures and as such, proper shot placement, adequate penetration, and multiple shots on target cannot be over emphasized. 5 Ibid.
Tactical Realities
Shot placement is paramount and law enforcement officers on average strike an adversary with only 20 – 30 percent of the shots fired during a shooting incident. Given the reality that shot placement is paramount (and difficult to achieve given the myriad of variables present in a deadly force encounter) in obtaining effective incapacitation, the caliber used must maximize the likelihood of hitting vital organs. Typical law enforcement shootings result in only one or two solid torso hits on the adversary. This requires that any projectile which strikes the torso has as high a probability as possible of penetrating deeply enough to disrupt a vital organ.
The Ballistic Research Facility has conducted a test which compares similar sized Glock pistols in both .40 S&W and 9mm calibers, to determine if more accurate and faster hits are achievable with one versus the other. To date, the majority of the study participants have shot more quickly and more accurately with 9mm caliber Glock pistols. The 9mm provides struggling shooters the best chance of success while improving the speed and accuracy of the most skilled shooters.
Conclusion
While some law enforcement agencies have transitioned to larger calibers from the 9mm Luger in recent years, they do so at the expense of reduced magazine capacity, more felt recoil, and given adequate projectile selection, no discernible increase in terminal performance.
Other law enforcement organizations seem to be making the move back to 9mm Luger taking advantage of the new technologies which are being applied to 9mm Luger projectiles. These organizations are providing their armed personnel the best chance of surviving a deadly force encounter since they can expect faster and more accurate shot strings, higher magazine capacities (similar sized weapons) and all of the terminal performance which can be expected from any law enforcement caliber projectile.
Given the above realities and the fact that numerous ammunition manufacturers now make 9mm Luger service ammunition with outstanding premium line law enforcement projectiles, the move to 9mm Luger can now be viewed as a decided advantage for our armed law enforcement personnel.
End of FBI release
Looking into their analysis, under “Permanent Cavity” they state that, “The extent to which a projectile expands determines the diameter of the permanent cavity which, simply put, is that tissue which is in direct contact with the projectile and is therefore destroyed (my emphasis). Then further down: “…an operating room surgeon or Medical Examiner cannot distinguish the difference between wounds caused by .35 to .45 caliber projectiles.”
Under the heading “Temporary Cavity” they state that, ““For the temporary cavity of most handgun projectiles to have an effect on wounding, the velocity of the projectile needs to exceed roughly 2,000 fps. At the lower velocities of handgun rounds, the temporary cavity is not produced with sufficient velocity to have any wounding effect; therefore any difference in temporary cavity noted between handgun calibers is irrelevant. “In order to cause significant injuries to a structure, a pistol bullet must strike that structure directly.” DiMaio, V.J.M.: Gunshot Wounds, Elsevier Science Publishing Company, New York, NY, 1987, page 42.””.
On the one hand they’re claiming that at normal handgun velocities only tissue that is directly contacted by the bullet is damaged. But then they claim that medical examiners can’t distinguish between wounds caused by bullets of different diameters. I doubt that any two wounds are ever exactly alike in all possible ways. Are we supposed to infer that in every conceivable way in which wounds can differ, no difference, however large or small, can be attributed to the diameter of the bullet? In light of the claim that only tissue in direct contact with the bullet is damaged, the implication seems contradictory to me.
Let me put it even more simply: the FBI is stating that the diameter of the permanent wound cavity is directly proportional to the diameter of the bullet. Assuming their claim that “only that tissue which is in direct contact with the projectile is destroyed” is true (and I’m not disputing that at the typically low traditional handgun velocities), I find it difficult to believe that bullet diameter would never have any effect on the size of the permanent wound cavity. A 9mm bullet must expand 13% to equal the beginning diameter of a .40 caliber bullet. Likewise, a .40 caliber bullet must also expand 13% to equal the beginning diameter of a .45 caliber bullet. A 9mm bullet must expand a whopping 27% to equal the beginning diameter of a .45 caliber bullet. When a bullet leaves the gun barrel it begins to constantly lose velocity. That’s true regardless of what it’s passing through (air, wood, metal, water, tissue) until it stops. When a bullet expands, its rate of deceleration increases at a rate proportional to the degree of expansion, along with the degree of resistance applied by the medium through which it’s passing. There is nothing profound here. It’s simply basic physics, or the application of Newton’s three laws of motion. Also, as velocities increase, “secondary projectiles” like bone fragments can cause damage such as the severing of arteries. Yes, they’re correct in saying that velocities much under 2000 fps rarely achieve this type of damage, but newer and lighter projectiles are reaching velocities that actually exceed that in some handgun calibers. There are several loads in .357 Sig that exceed 2100 fps with a barrier-blind, non-expanding bullet that offers large temporary AND permanent wound cavities, while still delivering well-above the minimum required penetration.
First of all, let me state unequivocally that I agree with the FBI’s decision to go back to the 9mm. Like their earlier decision to go with the .40; considering the times in which they were made, both decisions made sense. Modern bullet technology has shrunk the difference in terminal ballistic performance between calibers. This is an undeniable fact, and it lies at the heart of the FBI’s decision to go back to the 9 and take advantage of lighter guns, less recoil (resulting in faster repeat shots and more accurate shooting by agents), greater magazine capacity, and lower cost. But it would be naïve to infer from the FBI’s statement that modern projectile technology has turned handgun calibers into virtual ballistic twins, and I don’t believe that’s what they’re attempting to imply. Whether you believe these differences to be large or small, I maintain that they undeniably exist. Assuming my premise to be true, let’s look at what law enforcement officers and civilians must contend with in defending themselves, and how they usually differ.
Decisions that make sense for law enforcement agencies don’t necessarily make sense for an individual concerned with personal defense. When civilians are involved in a confrontation it’s nearly always because they’re targeted. Unfortunately in today’s society, this can also be true for law enforcement officers. But by and large, confrontations involving law enforcement result from them pursuing a person or persons, not the other way around. Usually, but not always, there is at least a little time to plan ahead, so more than one officer will likely be present. They will also likely have some control over the encounter because they’re usually the ones who are precipitating it. They often have time to implement, delay, or change tactical decisions based upon what is unfolding in real time. They base these decisions on trying to reach their goal of apprehending or neutralizing the bad guy(s) without getting themselves or other innocent parties killed in the process. When they engage in a two-way firefight, some shots must sometimes be taken at much longer distances than a civilian would encounter. These firefights may also last for an extended time. For these reasons it’s far more important for law officers to be able to fire accurately over longer distances and have a reasonably large reserve of ammunition. These concerns are rarely present in a civilian confrontation. But civilians have their own complications with which to contend. If a civilian must shoot at all in a violent encounter, it rarely involves more than a few rounds. By the time a shot is actually fired, the distance to the target is almost always less than five yards (and probably closing), often much less. This is especially true if the incident takes place in a public location. By the time we know beyond a reasonable doubt that we’re being attacked, it’s unfortunately already unlikely that we can draw our handgun and shoot before being reached. We don’t know ahead of time what the attacker’s intentions are. He isn’t someone we have identified and are seeking to apprehend. Additionally, the attack will almost always be a total surprise, instantly projecting us into a new reality, when a moment before it was likely the furthest thing from our mind. We may have some forewarning if we’re in our home or on our property, but it’s unlikely in public. We’re rarely afforded the luxury of identifying our target more than a moment or two ahead of time. In a typical civilian situation, the immediate effects (or lack thereof) of that first shot are usually much more consequential than in a law enforcement encounter. For these reasons, I want to carry something that gives me the best chance of stopping the assailant as soon as possible, before he can harm me or another innocent party. If my choice of handgun caliber raises my chances of surviving the encounter by only a small amount over that of another, I’ll take it. It’s extremely unlikely that a civilian would have to shoot at someone more than a few yards away. Decreasing my accuracy level by a few minutes of angle, or reducing my magazine capacity from 15 to 13, or raising my recoil recovery time by a few hundredths of a second aren’t near the top of my list of concerns. I already have far more important things with which to contend.
Like their earlier decision to adopt the .40, federal agencies deciding to return to the 9 drew the attention of state and local agencies, as well as the civilian market. The effects of their first decision to adopt the .40 were unprecedented in the world of caliber popularity. This also happened right in the middle of the easing of concealed carry laws throughout the country. It made the .40 skyrocket in popularity seemingly overnight. Gun manufacturers were falling over each other in their rush to offer their best products in the new caliber. But now, just as profoundly and just as quickly, their decision to go back to the 9 has put the popularity of the .40 into freefall. I don’t believe a firearm caliber has ever gotten so popular, and then so unpopular, as quickly as the .40, but there have never before been the combination of market forces in play that contributed to both anomalies.
The .357 Sig is also falling in popularity, though it was never nearly as popular as the .40. The .45 ACP is less popular for a carry sidearm than it once was, though I don’t believe this is only due to the resurgence of the 9. Smaller and lighter guns with high capacity double-stack magazines, regardless of caliber, were already taking a toll on the popularity of the .45 as a carry sidearm for civilians and law enforcement alike.
In 2019 the Secret Service dropped the .357 Sig in favor of going back to the 9. I believe all other federal agencies that were using the Sig have done so as well. There are still a few state and local police agencies using it. At this point I believe my favorite defensive handgun round is on life support. The .40 had gained enough of a following in the civilian market that it should be safe for the foreseeable future. I doubt that either cartridge will ever increase in popularity. Ammo manufacturers spend more time and effort developing loads for the 9mm than any other handgun round, and it’s a highly competitive market. Due to economy of scale and fierce competition, it should continue to be the most economical of the popular rounds to shoot, usually by a considerable margin. This is especially true of low-cost practice ammo, for which other popular rounds will cost you 1 ½ to 2 times more.
Though I love the .357 Sig, I don’t think I’ve ever recommended it when asked my opinion on what caliber a person should purchase for defensive carry. It’s just too expensive to shoot compared with anything else. I’m a handloader and can do so for the Sig if I so desire. If you’re in a position to not care how much your ammo costs then go for it, but if the cost cuts into how much you practice shooting your handgun then it’s a big mistake. I have a Sig P250 that I can convert to 9mm, .40, or .45. I can use it in 9mm for practice and it’s identical to my P250 .357 Sig, which I can also convert to any of the aforementioned calibers. .357 Sig ammo can also be difficult to find, regardless of price, and this situation isn’t going to get any better. During the last two serious ammo shortages though, popular ammo was almost impossible to find at times. During those times, you would sometimes see bare shelves except for the more exotic stuff, like the .357 Sig.
All calibers, not just the 9, have benefited greatly from advances in bullet technology. The .40 still has a ballistic advantage over the 9. The .45 still may have a ballistic advantage over both, depending on your personal parameters and biases. But these perceived advantages have shrunk, there’s no getting around it. All of this depends greatly on choice of ammo, so it’s meaningless unless you compare the same type of projectile and pressure (relative to maximum) of the load for each caliber. Penetration must always be given precedence over expansion, and expansion always reduces penetration. That’s just basic physics. Expansion is desirable unless or until it reduces penetration below the required minimum level. In a personal defense round, this is usually considered to be 12 inches in ballistic gelatin.
With the easing of concealed carry laws, the .380 has become hugely popular. Handgun manufacturers have flooded the market with new compact and subcompact offerings. It’s now possible to get a 9mm in a gun the size of which was once only available in a .380, but you can now get a .380 in a size that was once only the domain of the .32 and the .22 rimfires. But as you move down in size for any of these calibers a price must be paid in other areas, such as muzzle blast, recoil, and relative ease of gaining proficiency of use (often referred to as “shootability”). For some women, older people (read “arthritis age”) or others of smaller stature, it isn’t practical to move down in gun size without also moving down in power factor.
It’s far more difficult to produce ammunition in chamberings such a .380 ACP and .32 ACP to develop a load that will offer a desirable amount of expansion and still offer the required penetration. A bullet fired at the reduced velocities of these rounds rarely shows much expansion, especially in the short-barreled guns in which they’re normally used. This is also true of even the full-power calibers if chambered in a gun with a barrel much less than 4 inches. If the bullet does reliably expand, it’s often at the expense of the required minimum penetration. Because of this, many users opt for using FMJ or other non-expanding projectiles since, in an either/or situation, penetration must always be given precedence over expansion.
There are now projectiles on the market that are defying the conventional wisdom that dictates having to contend with this balance of penetration and expansion. They’re “monolithic” (one sold piece) and have flutes or other anomalous traits that create hydraulic pressure when traversing soft media. This results in a permanent wound channel similar to that of an expanded projectile, often even better. Because they don’t expand, they don’t sacrifice penetration in order to get that result. They’re also pretty much “barrier blind”, and show little to no deformation when going through glass, car doors. Etc. Clothing layers don’t seem to affect them at all. This makes them immune to the problem that hollow points sometimes experience when material such as drywall, clothing, or wood fills the cavity and prevents jacket expansion. I’ve been carrying cartridges with these new non-expanding bullets almost exclusively since 2013, regardless of caliber. With my .357 Sigs I can easily surpass the “roughly 1900” fps the FBI claims is needed to cause a temporary wound cavity to “have an effect on wounding”.
As significant as the improvement is that modern bullets have given us in the “full-power” calibers, it’s even more so in the less powerful ones such as the .380 ACP and .32 ACP. In conventional wisdom, expansion and penetration are the two attributes that define a bullet’s terminal performance. If, for whatever reason, you’re relying on the .380 ACP, or even the little .32 ACP, your choice in projectile is critical in order to reach a realistic level of performance for personal defense. Because solid fluted bullets (or other bullets with anomalous designs) penetrate so well, they offer the added advantage of being able to use a lighter weight bullet. This reduces recoil, increases velocity, flattens trajectory (not much of an advantage at defensive distances, but I’ll take it), and still results in more than enough penetration. The beneficial effects of fluted and similarly designed bullets is increased by velocity and, I believe, the attendant increase in RPMs. These projectiles have given me far more confidence whenever I find it necessary to carry my little pocket .380 as my only gun. I also have a little .32 ACP that I may carry on occasion for deep concealment, or as a backup. I always use either this type of projectile or a hard-cast lead flat point, or a mixture of both. I may not get any expansion, but I know that it will penetrate like there’s no tomorrow!