The Origin of the .40 S&W – An Ammo History Lesson

A .40 S&W Pistol

American firearms manufacturers Smith & Wesson and Winchester designed and debuted the .40 S&W (10 x 22mm Smith &Wesson) on January 17, 1990. This rimless pistol cartridge was developed in response to a horrific shootout between FBI agents and two serial bank robbers in Miami in 1986—albeit nearly four years later. The 9mm rounds that most of the agents shot the suspects with were ineffective in subduing them. This event led to the eventual need for more powerful ammunition for law enforcement. Thus, the origin of the .40 S&W is tragic yet necessary. It highlights the need for technology to continue to evolve in the face of new threats. This article will, therefore, provide an overview of the history of the .40 caliber and why it was made.

The Event That Highlighted a Need for More Power

It was April 11, 1986, when an otherwise bright spring day took a turn for the worse. Two suspects, named Michael Lee Platt and William Russel Matrix, were wanted for serial bank robberies. A few FBI agents were staking out a bank, looking specifically for a stolen Monte Carlo. There’s still no certainty on who tipped the agents off, but they found their suspects.

Many Bullets Were Fired at the Miami Shootout, and 2 FBI Agents Were Killed

The agents partially surrounded the suspects, but a firefight ensued in which a total of 140 bullets were fired. Platt and Matrix, the suspects, had weapons in their vehicle and returned fire on the agents. The type of weaponry the men had in their vehicle quickly outgunned the agents, and the situation turned grave very soon. The agents continued to fire several rounds at the suspects, most of which were 9mm rounds. It took 6 bullets to kill one of the suspects and 12 for the other. What was even more surprising was that the toxicology reports showed that the suspects hadn’t consumed any drugs or got any boost from chemicals to enable them to continue shooting despite taking several shots. Moreover, the agents shot in critical areas. The only deduction was that the 9mm rounds were not strong enough to put the suspects down effectively and quickly enough.

Unfortunately, this violent encounter led to the tragic death of two agents, while five were severely injured. The shootout only ended when the bad guys were killed, and to this day, this day in 1986 is considered as one of the most violent events in FBI history.

The Search for a New More Powerful Caliber Cartridge

There were undoubtedly immeasurable losses on April 11, 1986. The event showcased the inadequacy of the 9mm (be it the 9mm Luger, 9×19 Parabellum, or 9×19 NATO), and the severity of what was at stake led law enforcement to search for a new cartridge. The 9mm bullets didn’t suffice in taking down the bad guys quick enough, and now they needed a larger cartridge than the 9mm. Larger bullets would, in their understanding, be instrumental in helping special agents and officers stay tactically equipped for potential threats like the one that day in Miami.

The 10mm Auto Consideration

The 10mm Auto immediately became a cartridge that gained the FBI’s interest. In addition to that, partial blame was put onto the use of revolvers in the firefight—only a few agents used semi-automatic pistols. Revolvers increased the reload time, which could be disastrous in such situations, as was evident with the outcome of the Miami shootout. Other than faster reloading, semi-automatics also offered increased ammo capacity.

Therefore, the FBI chose the Smith & Wesson 1076, which was chambered for the 10mm Auto cartridge. However, it didn’t prove to be a good choice because it had a sharp recoil that made it difficult for most agents in the test to keep their aim in control. After that, the FBI started to test ammo that had a smaller powder charge for better control.

The Role the Colt Delta Elite 1911 Played in the .40 S&W Origin

The origin of the .40 S&W is, thus, rooted in what followed. So, John Hall, the Special Agent-in-Charge of the FBI Firearms Training Unit, brought his personal Colt Delta Elite 1911 to training. His firearm was chambered for the 10mm cartridge. After testing the weapon, with its reduced-power handloads, the agents learned that a 180-grain bullet that had 1,000 feet per second muzzle velocity offered both power and control. The FBI then decided to have the manufacturer Smith & Wesson produce the guns to those specifications for law enforcement use. The request was to develop a firearm similar to the design of the S&W Model 4506 .45 ACP handgun.

There Was No Longer a Need for a Larger Case

Eventually, the engineers determined that the large case as used in the 10mm Auto was not necessary to contain the smaller powder charge. The design had to the medium velocity specification by the FBI, so the case had more airspace because of the less powder.

Therefore, the manufacturers reduced the cased length from 0.992 inches to .850 inches. In addition to that, they changed the primer size to Small Pistol from Large Pistol. Thus, that is how the .40 S&W came into existence.

What the .40 S&W Offered

The origin of the .40 S&W enabled law enforcement to carry powerful firearms in a small package. The .40 S&W cartridge length is slightly smaller than the 9mm cartridge. Therefore, a .40 S&W cartridge could fit into a 9mm handgun, and it would simultaneously offer a significant increase in power compared to the 9mm rounds.

More Power Than the 9mm Rounds

The American firearms manufacturer Winchester produced the first ammunition. Therefore, the initial .40 S&W loads used 180-grain bullets that had 985 feet per second muzzle velocity. As a result, when fired, it would generate 388 ft-lb of muzzle energy.

More Muzzle Energy Than the 9mm Bullets

Later, the bullet weights increased to 200 grains from 125 grains. As a result, some .40 S&W loads generated approximately 500 ft-lb of muzzle energy. This amount of energy was significantly greater than the 350 ft-lb of muzzle energy generated by the 9mm rounds.

Greater Diameter and Size Than the 9mm Bullets

In addition to the muzzle energy, the size and weight of the .40 S&W bullet were more than the 9mm round. This factor is more important than the muzzle energy because handguns typically don’t produce nearly as high muzzle energy as a rifle. Therefore, what actually makes a difference in the stopping power of a handgun is the diameter of the bullet. A .40 caliber bullet is wider (and heavier) than a 9mm one, so it’s going to punch a bigger hole in its target. Also, considering that momentum increases with an increase in mass (weight in colloquial terms), the larger bullet can do more damage.

The Start of the .40 S&W

It was January 17, 1990, when the origin of the .40 S&W came to be official. The S&W Model 4006 pistol also debuted that day. However, the pistols were available for purchase several months after that. During that delay, the Glock Ges.m.b.H., an Austrian firearms manufacturer, got its pistols to dealers’ shelves in that year. The Glock 22 and Glock 23 were chambered for the .40 S&W, and it announced this release a week before the S&W made the 4006 available. Eventually, the Glock 22 and Glock 23 became the most common pistols that used the .40 S&W cartridge.

Most of the FBI Started Using the .40 S&W over the 10mm

The Austrian manufacturer managed to adapt the new cartridge very quickly because it had introduced a pistol, the Glock 20, that was chambered for 10mm Auto only a short while before that. Considering the similarity of the bore diameter and case head between the .40 S&W and the 10mm Auto, the adoption of the new design cartridge didn’t prove difficult.

This quick shift also resulted in many law enforcement agencies abandoning the 10mm, especially the FBI. However, the FBI SWAT teams and the Hostage Rescue Team use the 10mm.

The .40 S&W Became Common Among Law-Abiding Citizens

Other than becoming prevalent among various law enforcement agencies, the .40 S&W became popular among law-abiding citizens. So, many citizens began carrying handguns with these cartridges for self-defense.

Problems in the Initial Stages of the .40 S&W

Like with most cartridges, the origin of the .40 S&W also had a common problem. There were many reports of users, especially those using older Glock pistols, experiencing rupture failures with the .40 S&W. The cause was some barrels’ unsupported area around the case head. Therefore, there weren’t many problems with new factory loads. However, the problem stemmed from reloading, in which the cases were worked and became weak.

There is another explanation for this issue. So, the explanation is that the protruding area in reloaded cases is not removed completely when resizing. Therefore, the gun will fire slightly out of battery because of that. On the other hand, there’s also the theory that an unsafe pressure level was used for loading some of the loads.

In this day and age, this issue is not as prevalent as they were before, indicating that manufacturers have addressed it. Owners of .40 S&W cartridge handguns can also consider getting a special die made by Redding that removes the proverbial “Glock bulge” from the case.

The FBI’s Return to the 9mm

Even though the 9mm was deemed ineffective and partially held responsible for the tragic deaths of the 1986 Miami shootout, the FBI announced its decision to return to that caliber in 2015. This decision was made due to enhancements in ballistic technology. Therefore, there is a new 9mm round called the 147 grain Speer Gold Dot G2 by various gun aficionados.

A New 9mm Round That Offers More Penetrative Power

According to reports, the 9mm rounds in the 1986 event did not penetrate the suspects’ bodies well enough to kill them. It was deduced that one of the suspects, Michael Platt, died from the first shot. This bullet penetrated his chest cavity but didn’t get far enough to pierce his heart. That is why he continued to fight back despite being shot multiple times. In that time, he managed to kill two FBI agents and wound a third.

After improvements in ballistic technology, the new 9mm bullet offered more penetrative power. Therefore, it addressed one of the most critical issues that the agents faced during the 1986 Miami firefight.

FBI Special Agent Ray Cook said that this light bullet could reach its target faster than a heavier bullet would when fired from a gun. The testing conducted by the FBI concluded that this new 9mm round could penetrate 12 to 18 inches into the human body.

The New 9mm Round Offered Better Accuracy

The FBI ballistics testing also concluded that the lightweight of the 9mm cartridge allowed agents to get more accurate shots. The better accuracy was, of course, a factor that would help agents in gunfights.

Police Departments Are Following in the FBI’s Footsteps

Cook also claimed that the FBI had more resources for researching and testing weapons than various other law enforcement agencies. As a result, it can greatly influence police departments, which cannot conduct detailed research and tests of their own, to follow its decisions. Cook argued that local police departments often accept that decisions taken by the FBI will also serve in their interest. Therefore, various local police departments have experimented with shifting to the new 9mm rounds or have already done so.

What We Must Still Consider about the New 9mm Rounds

There’s no doubt that the 9mm rounds have improved over time, offering better penetration and overall stopping power for law enforcement personnel. However, there is one important aspect that we must still consider.

The 9mm Cartridge Is Still the Weakest Among the Three Handgun Cartridges

There are three defensive handgun cartridges: the .45 ACP, the .40 S&W, and the 9mm. The 9mm is the weakest out of these three because the upgrades in cartridge technology apply to all of these cartridges. Therefore, the terminal performance of the 9mm will be better than what it was in 1986, but it will still not offer any improvement from what the .40 S&W and the .45 ACP offer today. The only real advantage the upgraded 9mm cartridge offers is better recoil over the others.

Last Few Words

While the origin of the .40 S&W is clear, its future is still uncertain. These rounds have lost their popularity in law enforcement and civilian sales with the new 9mm upgrade. However, whether this shift is a trend or something that will stay, it’s important that we don’t let history repeat itself because the .40 S&W is still arguably the best self-defense handgun cartridge available.

If you’re looking for ammunition for your handguns or rifles, take a look at our stock at Patriot Defense Ammunition, an official distributor of Winchester ammunition. We’re a veteran, minority-owned and operated business that believes in your right to bear arms!