40 S&W vs 9mm Key Differences, Performance, and Pros and Cons

When it comes to choosing between .40 S&W and 9mm, gun owners often want to know which is better for everyday use. The main difference is that .40 S&W offers more power, while 9mm usually gives less recoil and higher magazine capacity. There are many factors to think about, like stopping power, ease of shooting, and cost.

Many shooters prefer 9mm for its lower recoil and affordable price, making it great for practicing and training. Others might choose .40 S&W because it has a little more power and makes a slightly bigger hole, which some consider better for self-defense. However, both calibers can perform well if used properly.

Key Takeaways

• .40 S&W has more power, while 9mm offers less recoil.

• 9mm is often cheaper and easier for training.

• Both are solid choices for self-defense and everyday carry.

Overview of 40 S&W and 9mm Cartridges

The .40 S&W and 9mm are both popular handgun cartridges used worldwide. They differ in origin, size, power, and the types of firearms in which they are found, making each one suited to different preferences and needs.

History and Development

Georg Luger designed the 9mm cartridge in 1902. It quickly became popular thanks to its use in military sidearms and police pistols worldwide. Its formal name is 9x19mm Parabellum, and it has become the most widely used pistol cartridge globally.

The .40 S&W was introduced in 1990. Smith & Wesson and Winchester created it for law enforcement looking for a balance between the stopping power of the .45 ACP and the capacity of 9mm rounds. The .40 S&W was first developed for use in the FBI’s semi-auto pistols after the 1986 Miami shootout.

Both have seen widespread adoption by police, military, and civilian shooters. Many law enforcement agencies in the U.S. used .40 S&W for years but are now switching back to 9mm for its lower recoil and higher capacity.

Technical Specifications

9mm (9x19mm Parabellum):

• Bullet diameter: 9.01 mm

• Case length: 19.15 mm

• Typical bullet weight: 115–147 grains

• Muzzle velocity: 1,100–1,300 fps

• Magazine capacity: usually higher than .40 S&W

.40 S&W:

• Bullet diameter: 10.16 mm

• Case length: 21.59 mm

• Typical bullet weight: 155–180 grains

• Muzzle velocity: 950–1,200 fps

• Magazine capacity: often lower than 9mm in the same-size guns

The 9mm is known for mild recoil, making it easier to shoot quickly and accurately. The .40 S&W uses higher pressure and energy, leading to stronger recoil and more muzzle blast. This can make .40 S&W firearms harder for new shooters to handle, but they fire heavier bullets with more stopping power per shot compared to 9mm. Both rounds can be found with a wide variety of bullet designs for different uses.

Popular Firearms Chambered

Both cartridges are used in many well-known handguns. The Glock 19 and Glock 26 are famous for being reliable 9mm models, with high magazine capacity and availability. Many police and civilian shooters prefer these for their size and performance.

For .40 S&W, the Glock 22, Glock 23, and Glock 27 are common choices. These pistols are similar in size and layout to their 9mm counterparts but are built to handle the increased pressures of the .40 S&W round. The SIG P229 is another popular .40 S&W option, known for its strong frame and smooth operation.

Some guns, such as specific Glock models, can even use a conversion barrel to switch between .40 S&W and 9mm, letting shooters take advantage of both cartridges with the same firearm frame and magazines. This flexibility is useful for training, cost savings, and adapting to different shooting roles. Each cartridge has a wide range of factory and aftermarket support for magazines, holsters, and parts.

Ballistics and Shooting Performance

The .40 S&W and 9mm differ in bullet energy, recoil, and performance when fired rapidly. Their unique characteristics affect stopping power, speed, and the ease with which shooters can stay on target.

Stopping Power and Energy

The .40 S&W cartridge carries more energy than the 9mm. This is because it usually fires a heavier bullet at a higher pressure.

A typical .40 S&W round travels between 950 and 1200 feet per second, delivering 400-500 foot-pounds of energy. In comparison, most 9mm loads deliver about 300-400 foot-pounds. This extra energy often leads to a larger and more damaging wound channel, which some shooters believe means better stopping power.

However, modern 9mm bullets with improved design perform well and are trusted by many law enforcement agencies. Both cartridges are considered effective for self-defense, but the .40 S&W still has an edge in raw power according to recent ballistics tests.

Recoil and Control

The .40 S&W's extra power brings more recoil. Some shooters find this makes the pistol harder to control, especially during rapid fire or when using only the support hand.

In comparison, the 9mm has lower recoil, which allows for better control. This can help shooters return to their sights faster after each shot. A shooter firing 9mm will likely notice less muzzle flip and can make follow-up shots more quickly and accurately than with a .40 S&W.

Those new to handguns or those with less grip strength often prefer the 9mm for its lower recoil and easier shooting experience.

Accuracy and Speed

Lower recoil in the 9mm usually means less movement during shooting. This allows for faster and more accurate follow-up shots in both rapid-fire and controlled conditions.

Magazine capacity is also higher in most 9mm pistols since the cartridges are smaller. More rounds between reloads can help maintain accuracy over longer shooting sessions.

Shooters report quicker shooting and better aim with 9mm, especially during rapid fire or stress drills. The .40 S&W may require more effort to control and can slow shooting speed, but well-trained shooters can still perform well with practice.

Ballistic Gelatin and Wound Channel

Ballistic gelatin tests show that both .40 S&W and 9mm rounds can penetrate deeply enough to reach vital organs. The .40 S&W usually creates a wider wound channel due to its larger bullet and higher energy, leaving behind more tissue damage.

Modern 9mm defense rounds, however, can expand reliably, providing impressive wound channels that are sometimes close to those of the .40 S&W. Both cartridges meet or exceed FBI standards for minimum penetration in ballistic gelatin.

A comparison of wound channels in gelatin often indicates the .40 S&W as slightly larger and more aggressive, but not by a huge margin. Yet, actual test results confirm that improvements in bullet design have narrowed the gap between the two in terms of tissue damage and penetration.

Self-Defense and Carry Considerations

When choosing between .40 S&W and 9mm for self-defense, users should consider recoil, magazine capacity, and the type of firearm they want to carry. Reliability, shooting comfort, and ammo effectiveness also matter to regular citizens and law enforcement.

Personal Defense Ammo Options

Both .40 S&W and 9mm offer a wide selection of personal defense ammo, with options like jacketed hollow points (JHPs) designed to stop threats quickly. Modern 9mm JHPs have improved a lot in the last decade, often performing close to or at the same level as .40 S&W in critical defense situations.

Many brands offer special defense ammo, like Federal HST or Hornady Critical Defense, for both calibers. Some shooters believe .40 S&W creates a larger wound channel and delivers more energy, which can result in better terminal performance. However, the 9mm allows for faster follow-up shots and increased magazine capacity.

Shooters use both calibers in compact and sub-compact carry guns. The slight increase in size of .40 S&W bullets may mean fewer rounds in similar-size pistols. People looking for lightweight, everyday carry often lean toward 9mm because of higher capacity and lower recoil.

Law Enforcement and Civilian Use

Law enforcement agencies have debated the value of .40 S&W versus 9mm for years. Many police departments started using .40 S&W because it offered more stopping power than 9mm and a bigger margin for error compared to smaller rounds like .380 or .357 SIG. Real-world data suggests .40 S&W may have a better record in some compiled self-defense incidents. You can read more about this in this discussion on Reddit.

Recently, more departments are switching back to 9mm. Reasons include better accuracy, softer recoil, and advancements in 9mm ammo that rival .40 S&W’s performance. Civilians also find 9mm easier to shoot, especially in compact pistols that are common for carry.

Larger calibers like .45 ACP and 10mm remain popular with some, but most people agree that proper shot placement and good JHP ammo are more important than caliber alone. Agencies and individuals want reliability, manageable recoil, and rapid follow-up shots.

Carry Comfort and Concealability

Comfort and concealability play a major role in caliber choice for daily carry. 9mm pistols are lighter, slimmer, and easier to conceal under regular clothes or in a small holster. Carrying a 9mm sub-compact or a compact pistol is manageable for a full day, especially for people with smaller frames.

.40 S&W pistols can feel heavier and may have more noticeable recoil, particularly in smaller carry guns. Muzzle flip can slow down follow-up shots, so some shooters choose 9mm to balance comfort with performance.

Magazine capacity is another factor. 9mm handguns often hold 2–3 more rounds compared to .40 S&W versions of the same size. Night sights, grip texture, and holster fit are important features as well, but many find 9mm more practical for everyday carry needs.

For people looking for discretion and all-day comfort, 9mm offers several compact and sub-compact choices with effective self-defense ammo. Carrying .40 S&W may make sense for those who value power over capacity and are comfortable with the extra weight and recoil.

Practical Factors: Availability, Cost, and Training

The price and supply of ammunition affect both new shooters and experienced gun owners. The ability to find affordable rounds for training and regular use is a major factor in caliber selection.

Ammunition Cost and Availability

Ammunition prices can add up quickly, especially with frequent trips to the indoor range. 9mm FMJ is usually more affordable, with prices around $0.50 per round, compared to about $0.60 per round for .40 S&W FMJ. Price differences can be greater for specialty or defensive ammunition.

9mm rounds are widely available in most stores and online shops. This makes them easy to find in bulk, which helps lower costs for both practice and stockpiling. For those who reload their own ammo, 9mm brass is standard and often less expensive than .40 S&W brass.

In comparison, while.40 S&W is not rare; it may not be available in as many stores, especially in smaller markets or during shortages. This can cause higher prices and limited options for defensive and practice loads. More people are choosing 9mm and .38 Special, and they are also sometimes easier to find than .40 S&W.

Training and Logistics

Lower recoil and cheaper ammunition make training with 9mm handguns easier for most shooters. Since more rounds can be bought for the same price, shooters often practice more with 9mm than with .40 S&W. This means more time on the range, which can lead to better skills and confidence.

For law enforcement and security, using one caliber across many guns reduces training costs and simplifies logistics. It also makes it easier to log ammunition used during sessions and replace training supplies. Indoor range rules often allow both calibers, but the lighter recoil and less snap of 9mm is less likely to cause fatigue, especially during long sessions.

People who reload ammunition may also find 9mm brass easier to collect, clean, and reload than .40 S&W. Simple cleaning methods, such as washing brass with motor oil, work for both. However, 9mm's smaller size lets shooters load more rounds at once for practice or competition. Classic revolver calibers like .38 Special and .45 LC are less common in semi-automatic pistols, but some training habits transfer between them.

Frequently Asked Questions

The .40 S&W and 9mm each have their balance of recoil, stopping power, and ballistics. These cartridges are often compared for self-defense and law enforcement because they serve similar roles but with different strengths.

What are the differences in stopping power between 9mm and .40 S&W ammunition?

The .40 S&W is often noted for its higher stopping power compared to the 9mm due to using heavier bullets and producing more energy per shot. However, modern 9mm cartridges have improved, with advanced bullet designs closing the gap in stopping power. Many law enforcement agencies continue to use 9mm because of its effectiveness and reduced recoil.

How does the size comparison between .40 caliber and 9mm rounds impact their performance?

.40 caliber bullets are larger in diameter than 9mm bullets. This means .40 S&W can make a wider wound channel. Still, the increased cartridge size usually means reduced magazine capacity. 9mm rounds allow for more shots per magazine and have less recoil, helping with control and faster follow-up shots.

Can .40 S&W rounds provide advantages over 45 ACP in self-defense situations?

.40 S&W rounds often offer higher magazine capacity compared to .45 ACP while maintaining good stopping power. The recoil is usually less than that of a .45 ACP but more than that of a 9mm. The .40 S&W can provide a compromise for shooters who want more power than a 9mm but want to avoid the heavier recoil and lower capacity of .45 ACP.

What does the ballistic performance chart indicate about .40 S&W compared to 9mm?

Ballistic performance charts show that .40 S&W generally produces higher muzzle energy and heavier bullets compared to 9mm. Ballistics data suggest that .40 S&W can penetrate deeper and create larger wound channels. However, 9mm typically offers higher velocities and less recoil, making it easier for many people to shoot.

In terms of power and recoil, how do .40 S&W and 10mm compare?

The 10mm Auto offers higher velocity and much greater energy than .40 S&W, making it even more powerful. However, with this extra power comes more recoil and harder handling. The .40 S&W was designed to offer a balance—more manageable recoil than 10mm, but still greater power than 9mm.

Is there a significant difference in ballistic performance between 9mm, .40 S&W, and .45 ACP?

There are real differences between these three rounds. .45 ACP uses the heaviest bullets and has the slowest speed, resulting in high recoil and lower capacity. 9mm is lighte and faster, and allows for more rounds per magazine. .40 S&W falls in between, providing more power than 9mm and a higher capacity than .45 ACP. Ballistics charts reflect these trade-offs with different bullet weights, velocities, and energy levels.