How the Ammo Compares: 10mm vs 40

10mm vs 40 Ammo Comparison

With exciting histories and several similarities and differences, the 10mm and the 40 Smith and Wesson are two bullets we are comparing today. Here’s a look at the different facts about two types of ammo: 10mm vs 40 that are marketed as being different but are pretty similar.

The 10amm auto cartridge has a height around 0.992 inches and travels an average speed of 1,199 feet per second (fps) from a gun with a six-inch barrel. It has around a 546-foot pound for every square inch of energy.

Practical Gunsmithing for Beginners: A Simple guide to gunsmithing and...
  • Amazon Kindle Edition
  • Webster, Wayne (Author)
  • English (Publication Language)

Gunsmithing for Beginners: How To Learn To Customize, Repair, And...
  • Amazon Kindle Edition
  • Wilder, Ted (Author)
  • English (Publication Language)

40 SW Measurement

10mm vs 40 SW

On the other hand, the 40 Smith and Wesson (SW) has a height around 0.85 and travels about 1,074 feet per second when shot from a gun with a six-inch barrel. The 40 SW has about a 423-foot pound per square inch of energy.

The comparative measurements between the 10mm v 40 SW are slightly different, but the reality is that the .40 is a short 10mm. Here’s a look at the history of each bullet.

History of the 10mm

10mm vs 40 ammo

While the history of the 10mm begins with Colonel Jeff Cooper who believed there needed to be a pistol caliber that was able to reach at least fifty yards, it was a combination of his invention and a gunfight between FBI and bank robbers who set the 10mm action into motion.

The Complete Guide to Gunsmithing: Gun Care and Repair
  • Skyhorse Publishing
  • Chapel, Charles Edward (Author)
  • English (Publication Language)

Gunsmithing For Beginners: Learn To Repair, Customize, And Refinish To...
  • Amazon Kindle Edition
  • Bomberger, Armando (Author)
  • English (Publication Language)


In Miami on April 11, 1986, there were eight FBI agents who located two bank robbers who were wanted. A firefight broke out and both bank robbers, Matix and Platt, plus Special Agents Grogan and Dove were all killed. The deaths of the Special Agents rocked their community and the nation.

Autopsies performed on the two crooks, and the results showed that the guns the Special Agents used, 9 mm’s, did not have enough power to penetrate the thieves. If the Agents had hit one of the crooks just one inch more, Special Agents Grogan and Dove most likely would have lived.


After realization, FBI Agents could’ve lived, Cooper’s idea about the 10mm auto came to life in the law enforcement arena. The first pistol used with the 10mm Auto was the Bren Ten. Most people recognize that gun because of the TV show called Miami Vice. After fall of the Bren Ten model, 10 mm embraced by Smith & Wesson. And they developed their Model 1076 and 1006. The Model 1076 was initially chosen by the FBI.

Eventually, Colt invented the Delta Elite, known as first 1911 pistol that had its chamber developed to work with a 10 mm Auto.

It didn’t take long after the introduction of 10mm for shooters to determine that there’s a lot of case capacity unused. And they worked to shorten it. The shortened version of 10mm became .40 Smith and Wesson. The famous cartridge used by law enforcement in America.

Here’s more about the history of  the 9mm:

History of the 40

10mm vs 40 ammo

Many people compare the 10 mm vs 40 because they do share similarities in their features, and also in their history. Like the 10mm, the FBI is the reason the 40 Smith and Wesson exists. The story of its beginning also started in April of 1986, during the same gunfight. Besides the two bank robbers and the two FBI Special Agents who were killed, five other Agents were also injured.

Gunsmithing Made Easy: Projects for the Home Gunsmith
  • Hardcover Book
  • Towsley, Bryce M. (Author)
  • English (Publication Language)

The Beginner's Guide to Reloading Ammunition: With Space and Money...
  • Gregersen, Steven (Author)
  • English (Publication Language)
  • 152 Pages - 01/25/2013 (Publication Date) - CreateSpace Independent Publishing Platform (Publisher)

Testing Using Ordinance Gelatin

testing using ordinance gelatin on 10mm vs 40 ammo

The experience spurred the FBI into action, and they began testing using ordnance gelatin to observe bullets in action, looking for ones that were able to penetrate and also expand. Their goal was to find a shot that could incapacitate someone more quickly than the 9mm did.

The first bullet the FBI asked the Federal Ammunition to create was the 10mm. The early testers used a 180-grain bullet that had a smaller recoil than the .45. The 10mm was impressive, and that is what they initially began using.

Eventually, S&W was asked to create a smaller 10mm cartridge case that had the same ballistics as a 10mm, and that is how the 40 SW was formed. After it was introduced, it became a popular choice in law enforcement because of the faster speed and the lumbering. It is a high compromise bullet.

Holds More Ammunition

A .40 SW holds more ammunition than .45 ACP but also keep heavier bullets than the 9mm. Once .40 became the top gun choice for law enforcement, it also gained popularity in the civilian territory.

After a while, there are problems with .40, with the most significant issue being caused some guns to explode. And also that they had an issue with separation of case heads. Those issues have been addressed, the fact 40 SW still the most popular ammo choice for Law Enforcement is controversial to gun experts.

Many people agree that 40 SW is a good compromise between the fast bullet and heavy one. However, it seems only a prominent bullet is met with perfect conditions. If there is a 140 to 155-grain projectile, the 40 works the best.

While it is still up for debate among gun enthusiasts, the .40 Smith & Wesson is still one of the top-selling ammunitions.

Comparison of the 10 mm and the 40 SW

10mm vs 40 comparison

For comparison of the 10 mm v the 40 SW, here is a look at several of the different features of each.


The recoil between both types of ammo is vastly different. The 40 has a short relative recoil, also known as a rifle recoil. The 10 mm has a much more significant recoil than the 40.


The width of both bullets is about the same size which makes the ability equal for both types. The capacity of the 10mm and the 40 SW are both fifteen rounds.

Every Day Use

Because of the recoil of the 10 mm, most people do not carry them unless they are not sensitive to the recoil. For law enforcement, the 40 is preferred. While it isn’t the bullet that hits the hardest, law enforcement appreciates the 40 because it hits hard enough to incapacitate but also is one of the best types of ammo for the fastest follow-up shots.

When Should You Carry a 10mm?

There are a few reasons why some people opt to carry the 10 mm. Here are two of them:

  • People who have been trained to handle the recoil of the 10 mm are the only ones who should be using them.
  • People who spend time outdoors in areas where they may see different bears, like black bears, mountain lions, or any other predators that are medium-sized. While it can work for some large predators, it isn’t always the best choice.

Making Ammo: A Beginner's Guide to Handloading
  • Kyle Lynch (Author)
  • English (Publication Language)
  • 240 Pages - 12/29/2014 (Publication Date) - Whitman Publishing (Publisher)

Ammo & Ballistics 6: For Hunters, Shooters, and Collectors
  • Forker, Robert (Author)
  • English (Publication Language)
  • 544 Pages - 06/05/2017 (Publication Date) - Safari Press (Publisher)

Rounds that are Comparable to a 10mm

  • The .357 Magnum has an average FPSI of 528.
  • The .357 SIG has an average FPSI of 515.

When Should You Carry a 40 SW?

There are many reasons why people choose to carry a 40, here are a few of the top ones:

  • Anyone who is sensitive to a high recoil should definitely avoid the 10mm. Recoil sensitivity is an essential factor, and the 40 is a good gun for anyone who wants a low recoil.
  • People who are located in an urban area would do better with a 40.
  • Law enforcement officials who need an impactful gun that doesn’t overdo it.

Rounds that are Comparable to a 40

When comparing rounds, you will look at the FPSI (energy). Here are the rounds closest to the 40 SW:

  • The .45 GAP has an average FPSI of 414.
  • The .327 Federal Magnum has an average FPSI of 452.

Conclusion of 10mm vs 40

10mm vs 40 ammo

The debate continues about the 10 mm vs 40 SW. While they do share similarities in history, ballistics and capacity, the two guns are very different because of the recoil and their individual purposes.

If you are looking for a gun with some power but low recoil, and you plan to carry it in urban places, for safety, the 40 SW is the best gun for you. If you want a gun that feels a lot like a revolver but has a capacity of a semiautomatic pistol, the 10 mm is right for you.

Guns & Ammo
  • Amazon Kindle Edition
  • Outdoor Sportsman Group (Author)
  • English (Publication Language)

The Practical Guide to Reloading Ammunition: Learn the easy way to...
  • Amazon Kindle Edition
  • McHale, Tom (Author)
  • English (Publication Language)

No Wrong Choice

As far as handguns go, there really isn’t a wrong choice between the 10mm vs 40 SW. Both guns have significant benefits for the people who need to use them.

There have been many bank robberies in history but the gunfight that ensued on April 11, 1986, was paramount in the gun world. It was only after the FBI possibly unnecessarily lost two of their men that the 10 mm and then the 40 SW came to be. Since then, the 40 has stood the test of time for law enforcement officials because of its powerful impact with low recoil. For people who love the power of a gun, the 10 mm has remained a popular choice.

About the author


Leave a comment: