10mm vs 9mm – Which Is Better?

The 9mm Parabellum has been ruling the handgun industry for more than a decade now. From the Luger pistols of the WW1 German soldier, and all the way up to the concealed carry holster of today’s gun bearing average Joe. It has been an incredibly popular and versatile cartridge. 

This comparison will test the elegance of the 9mm against the destructive hard-hitting power of the 10mm Auto which has now established itself as a popular bear defense and even self-defense gun. 

Although there’s only a difference of one millimeter between these two cartridges on paper, the actual story on the ground is immensely different. 

10mm vs 9mm

Check out this quick comparison of the pros and cons of the 10mm vs the 9mm

10mm Overview

The 10mm Auto, also known as the 10mm Automatic, is a rimless semi-automatic pistol cartridge that fires a .40 cal bullet. It was developed in 1983 by Col. Jeff Cooper and later adopted for production by Norma Precision AB (also simply known as Norma, which is a Swedish firearms manufacturer).

A more powerful version of this cartridge was introduced in the Bren Ten pistol developed by Dornaus & Dixon Enterprises, Inc. in 1983. The pistol indeed became a failure due to quality issues arising as a result of a rushed production, plus the exorbitant price, and was discontinued in 1986, just after three years of its introduction. 

However, the good days of the cartridge returned in 1988 when the Federal Bureau of Investigation started testing it for adoption. It is also said that Col. Jeff Cooper started developing the 10mm especially for FBI agents. The FBI and several other state police departments adopted the cartridge in a limited capacity with exceptional results and lethality. 

A less powerful version of this cartridge was developed in 1990 which came to be known as the .40 S&W. Although the 10mm Auto was found very effective in terms of trajectory and power, its high recoil, and the large resulting size of the handgun made it less controllable for the newbie or small-handed users. 

Even after all this, many state police departments, FBI teams, and SWAT teams still use weapons chambered for the 10mm Auto. It is also among the very few handgun cartridges that have been widely approved for hunting deer in the U.S. It is also very popular as a bear defense handgun. 

9mm Overview

The 9x19mm Parabellum, colloquially known as the 9mm is undoubtedly one of the most successful cartridges to ever exist. Also known as the 9mm Luger (since it was designed for the Luger semi-automatic pistol), this rimless, tapered cartridge was developed by the Austrian firearms designer Georg Luger in 1901. It is a rimless, tapered cartridge that fires a 0.355-inch bullet. 

This round was the refinement of the 7.65x25mm Borchardt (also developed by Georg Luger) into the 7.65x21mm Luger and finally into the 9mm Luger by cutting the size. This round was adopted by the German Military in 1904 and has since been into military service across many nations, including both NATO and non-NATO aligned countries. 

The 9mm was widely used as a handgun cartridge and submachine cartridge during the first and second world wars. It is undoubtedly the most popular handgun cartridge in existence today and is preferred by defense forces and civilians alike. Variations like the Commonwealth Standard, NATO standard, +P rounds, and M39 are also in existence. 

The low recoil makes this round very controllable, and the small size ensures a small magazine can fit more rounds. These two qualities make it an extremely popular handgun cartridge. 

10mm vs 9mm: Cartridge Specs

Here’s a quick table defining the cartridge dimensions for the 9mm and 10mm rounds. 

	10mm	9mm
Bullet Diameter	.4005 in (10.17 mm)	0.355 in (9.10 mm)
Neck Diameter	.423 in (10.7 mm)	0.380 in (9.65 mm)
Base Diameter	.425 in (10.8 mm)	0.391 in (9.93 mm)
Case Length	.992 in (25.2 mm)	0.754 in (19.15 mm)
Overall Length	1.260 in (32.0 mm)	1.169 in (19.69 mm)
Case Capacity	24.1 grains	13.30 grains
Max Pressure (SAAMI)	37,500 psi	35,000 psi
Typical Casing Material	Brass	Brass
Typical Bullet Weight (gr)	155-200 grains	115-147 grains

This comparison table quickly concludes two points. First, the 10mm is a bigger and fatter cartridge, and it fires heavier and larger bullets. The 10mm round seats a .40 caliber bullet and has a case length close to an inch. Whereas, the 9mm fires a 0.355-inch bullet and has a case length close to a quarter of an inch. 

The 10mm case holds almost twice as much powder as the 9mm and is loaded at a pressure of about 2,500 psi more than it. Although there are +P 9mm loads that can touch that mark and deliver some more velocity. 

The overall length of the 10mm round is about a centimeter over the 9mm. Additionally, the 10mm is also a fatter round due to its case capacity. This means that more rounds of the 9mm can be accommodated in a magazine of the same size. 

Another important difference to notice is that the 10mm fires heavier bullets than the 9mm. Where the 9mm can go as high as 147 grains, the 10mm can handle bullets as heavy as 200 grains. 

10mm vs 9mm: Ballistics

This ballistics section here will deal with the movement and energy characteristics of bullets fired from these cartridges. The study of ballistics gives us a better idea about how a bullet performs along the flight path. The three major characteristics studied under ballistics are trajectory, velocity, and kinetic energy. 

10mm vs 9mm: Trajectory

Here is the detailed data about the study of the trajectory of 10mm Auto and 9mm bullets. The most common bullet designs and bullet weights have been chosen to ensure a reasonable comparison. 

10mm

5”barrel/BC 0.14/165 grains Cor-Bon JHP	5”barrel/BC 0.170/180 grains Hydra-Shok	5”barrel/BC 0.210/200 grains Fusion Soft Point
25 yds: 0 “ Drop	25 yds: 0 “ Drop	25 yds: 0 “ Drop
50 yds: 0.10 “ Drop	50 yds: 0.7 “ Drop	50 yds: 0.70 “ Drop
75 yds: 1.96 “ Drop	75 yds: 3.7 “ Drop	75 yds: 3.2 “ Drop
100 yds: 5.77 “ Drop	100 yds: 9.1 “ Drop	100 yds: 7.6 “ Drop
125 yds: 11.68 “ Drop	125 yds: 17.20 “ Drop	125 yds: 13.9 “ Drop

9mm

4.49” barrel/BC 0.120/115-grain FMJ	4.49” barrel/BC 0.150/124-grain JHP	4.49” barrel/BC 0.200/147-grain FMJ
25 yds: 0 “ Drop	25 yds: 0 “ Drop	25 yds: 0 “ Drop
50 yds: 0.9 “ Drop	50 yds: 0.9 “ Drop	50 yds: 1.4 “ Drop
75 yds: 3.7 “ Drop	75 yds: 3.8 “ Drop	75 yds: 5.2 “ Drop
100 yds: 8.7 “ Drop	100 yds: 8.8 “ Drop	100 yds: 11.5  “ Drop
125 yds: 16.1 “ Drop	125 yds: 16.1 “ Drop	125 yds: 20.3 “ Drop

The table above compares the trajectory of both these rounds out to 125 yards. The definition of long range for a handgun varies from person to person. There have been shooters like Jerry Miculek who can hit a target at 1,000 yards with a 9mm revolver. Although, we are talking in general terms here, so under 50 yards is normal range, 75 yards is a medium range, and 100 yards and above is long range. 

Looking at the 10mm data, the bullets fire pretty much flat for a heavy bullet fired from a handgun. As you can already see the humongous 200-grain bullet in 10mm drops only at 13.9 inches at 100 yards. 

Moving on to the 9mm, the heavy 147-grain bullet drops to about 20 inches, whereas the lighter bullets show a considerably less drop of 16.1 inches. 

Comparing the trajectory of both these rounds side-by-side, the 10mm definitely comes out to be a flatter shooting round. A major contributor to this behavior is the extra powder and pressure characteristics. 

10mm vs 9mm: Velocity & Kinetic Energy

After analyzing the trajectory, let us now take a look at the velocity and energy characteristics of these rounds. 

10mm

5”barrel/BC 0.140/165 grain Cor-Bon JHP	5”barrel/BC 0.170/180 grains Hydra-Shok	5”barrel/BC 0.210/200 grains Fusion Soft Point
25 yds: 1,173 ft/s, 504 ft.lbs	25 yds: 998 ft/s, 398 ft.lbs	25 yds: 1,153 ft/s, 591 ft.lbs
50 yds: 1,110 ft/s, 451 ft.lb	50 yds: 970 ft/s, 376 ft.lbs	50 yds: 1,112 ft/s, 549 ft.lbs
75 yds: 1,058 ft/s, 410 ft.lbs	75 yds: 945 ft/s, 357 ft.lbs	75 yds: 1,077 ft/s, 515 ft.lbs
100 yds: 1,015 ft/s, 377 ft.lbs	100 yds: 921 ft/s, 339 ft.lbs	100 yds: 1,045 ft/s, 485 ft.lbs
125 yds: 978 ft/s, 350 ft.lbs	125 yds: 900 ft/s, 323 ft.lbs	125 yds: 1,017 ft/s, 460 ft.lbs

9mm

4.49” barrel/BC 0.120/115 grain FMJ	4.49” barrel/BC 0.150/124 grain JHP	4.49” barrel/BC 0.200/147 grain FMJ
25 yds: 1,106 ft/s, 312 ft.lbs	25 yds: 1,095 ft/s, 330 ft.lbs	25 yds: 976 ft/s, 311 ft.lbs
50 yds: 1,048 ft/s, 280 ft.lbs	50 yds: 1,049 ft/s, 303 ft.lbs	50 yds: 953 ft/s, 293 ft.lbs
75 yds: 1,001 ft/s, 256 ft.lbs	75 yds: 1,010 ft/s, 281 ft.lbs	75 yds: 933 ft/s, 284 ft.lbs
100 yds: 961 ft/s, 236 ft.lbs	100 yds: 977 ft/s, 263 ft.lbs	100 yds: 914 ft/s, 273 ft.lbs
125 yds: 927 ft/s, 219 ft.lbs	125 yds: 948 ft/s, 247 ft.lbs	125 yds: 896 ft/s, 262 ft.lbs

Let us first understand the velocity characteristics of these rounds. What is evident from the data is that the 10mm is almost always a supersonic round out to 100 yards. However, the 9mm has a supersonic range of mostly within 75 yards. 

As a general rule of thumb, a bullet is considered more accurate out to a distance to which it stays supersonic. Since the trajectory characteristics of a supersonic bullet are more predictable. The 10mm round has an edge over the 9mm due to the double case volume which holds more powder, and also a higher case pressure. 

While with lighter comparable bullet weights, the difference in velocity is around 50 fps. With heavy bullets, this gap widens out to about 100 fps.  

Now let’s move on to the energy characteristics. The 10mm bullets deliver around 500-600 fpe at 25 yards, which does not degrade too quickly out to 100 yards. Compared to that, the energy of a 9mm bullet starts around 300 fpe and reduces to about 230 fpe on average out to 100 yards. 

It is also important to note that different bullets will have different energy characteristics. Additionally, looking at the data, the 10mm retains almost twice the power of the 9mm at 50 yards. However, it is also evident that both these rounds are quite lethal out to 125 yards for a human. 

10mm vs 9mm: Stopping Power

The stopping power of a bullet is the measure of its power to incapacitate or obliterate a target and make it ineffective. For non-living things, it can be seen as the ability to penetrate armor or an object. For living beings, it explains the ability to wound or kill them. The least number of rounds it takes to do that, the better will be the stopping power. 

10mm vs 9mm: Momentum & Sectional Density

Here is the data covering the momentum and sectional density values of these two rounds.

Sectional Density: https://www.vcalc.com/wiki/MichaelBartmess/Sectional+Density

Momentum: Example: 45 caliber 240 grain bullet 200 yard velocity of 985 fps. 

240 x 985 = 236400 divided by 226,000 = 1.046 pound-seconds momentum.

10mm

5”barrel/BC 0.140/165 grains Cor-Bon JHP Sectional Density: 0.147	5”barrel/BC 0.170/180 grains Hydra-Shok Sectional Density: 0.161	5”barrel/BC 0.210/200 grains Fusion Soft Point Sectional Density: 0.179
25 yds: 27- ft.lb-s	25 yds: 25 ft.lb-s	25 yds: 32 ft.lb-s
50 yds: 26 ft.lb-s	50 yds: 24 ft.lb-s	50 yds: 31 ft.lb-s
75 yds: 24 ft.lb-s	75 yds: 24 ft.lb-s	75 yds: 30 ft.lb-s
100 yds: 23 ft.lb-s	100 yds: 23 ft.lb-s	100 yds: 29 ft.lb-s
125 yds: 23 ft.lb-s	125 yds: 23 ft.lb-s	125 yds: 29 ft.lb-s

9mm

4.49” barrel/BC 0.120/115 grain FMJ Sectional Density: 0.130	4.49” barrel/BC 0.150/124 grain JHP Sectional Density: 0.141	4.49” barrel/BC 0.200/147 grain FMJ Sectional Density: 0.167
25 yds: 18 ft.lb-s	25 yds: 19 ft.lb-s	25 yds: 20 ft.lb-s
50 yds: 17 ft.lb-s	50 yds: 18 ft.lb-s	50 yds: 20 ft.lb-s
75 yds: 16 ft.lb-s	75 yds: 17 ft.lb-s	75 yds: 19 ft.lb-s
100 yds: 15 ft.lb-s	100 yds: 17 ft.lb-s	100 yds: 19 ft.lb-s
125 yds: 15 ft.lb-s	125 yds: 16 ft.lb-s	125 yds: 18 ft.lb-s

The sectional density of a bullet is the ratio of its diameter and weight. The higher the value of this SD, the better penetration will be offered by a bullet. It is also important to understand that the design of a bullet also plays an important part here. A pointier bullet of a smaller mass can have an SD equal to a flatter bullet with a higher mass. 

To give you an idea of how much penetration the SD offers. An SD of less than 0.220 is good for small game, an SD of less than 0.270 is good for deer, and an SD of less than 0.300 is good for elk-sized game animals. This classification may vary based upon if a round is a small bore, medium bore, or big bore. 

Now some people may argue that I vouched for the 10mm earlier in this article as an effective deer hunting round. However, the SD data does not support that. So the thing here is, that SD is only a measurement of penetration, and other factors come into play. These are velocity, energy, bullet size, and momentum. 

The momentum is the measure of the effectiveness of energy transfer from the moving bullet to the object being impacted. The 10mm has almost 40% more momentum than the 9mm at any given range, and the larger bullet diameter helps create a big wound cavity. The 10mm delivers slightly more power than the .357 magnum and slightly less than the .41 magnum. 

10mm vs 9mm: Use Cases & Effective Range

The 10mm has been around for quite a while, and there is a lot of data to analyze the best applications and use cases for this round. 

Self and Home Defense

The 10mm was picked up by the FBI for its lethality and effectiveness. It is used by many police departments for their SWAT teams. It can certainly be used for self-defense and home defense situations. Comparing the 10mm and 9mm for self-defense is like comparing the sledgehammer with a hammer. 

The sledgehammer hits hard, but needs more strength and has a lesser number of hits. Whereas the hammer can deliver more hits and is very easy to control. 

The 10mm was phased out from widespread active service because it had a lot of recoils and lesser mag capacity compared to the venerable 9mm. As far as humans are concerned, they can be lethally hurt by a BB gun. So the 9mm eventually comes out as the better choice. 

Additionally, the 9mm feels more controllable in a stressful situation and their handguns are compact enough to be handled by shooters of any size. The 9mm is great for EDC when compared to the 10mm. 

Deer Hunting and Bear Defense

A lot of states allow 10mm Auto to be used for deer hunting. That’s because .30 caliber and bigger bullets are considered suitable for hunting deer. Many people claim that it takes at least 1,000 fpe of energy to effectively kill a deer. The 10mm completely busts this myth because it is legal to hunt deer with, and many people have taken down whitetails using a 10mm at ranges as far as 75 yards. 

If you are out on a hunting or camping trip in bear country, the 10mm is best for defense against bears. In fact, it is a very popular bear defense handgun and ranks above other options like the .357 Magnum due to its semi-auto pistol options and controllability. 

On the other hand, the 9mm is also an effective round. In fact, it uses a bullet which is the minimum recommended caliber for deer hunting in all states. A 9mm can hunt a deer within 20 yards with the right shot placement. However, I will recommend doing so. Plus, as far as bear defense is concerned, the 9mm was not designed for it and will not help with that. 

Competitions

While the 9mm is extensively used in competitions for its controllability, the 10mm is a rare sight in USPSA competitions due to its recoil. The 9mm is perfect for competitions and a lot of marksmen use it. 

10mm vs 9mm: Costs, Availability, & Compatibility

The 9mm and 10mm are very popular cartridges, but are they readily available and offer versatility?

Cheap and Abundant vs Somewhat Cheap and Scarce

The 9mm has been around for 121 years now and it is the most popular handgun cartridge in the world. The cartridge is super abundant and there is nowhere in the world where you can’t find 9mm ammo in a gun shop. Even the recent Covid-19 pandemic buying did not put 9mm extensively out of stock, but it raised its prices by a bit. 

The 10mm is a popular round, but it is not as abundant as the 9mm. Not every gun store will carry 10mm ammo, and it can be pretty hard to find especially if you are looking for some special ammo. 

Talking about the price, the 9mm is almost half the price as the 10mm. That’s simple supply and demand mathematics, so there is nothing to frown upon. 

Wide Range of Ammo and Gun Options

Both these cartridges have a wide range of rifle options available on the market. The 10mm cannot beat the 9mm in terms of versatility, but almost every major handgun manufacturer sells a handgun chambered for the 10mm. 

The ammo for 9mm is more abundant and has a lot of options compared to the 10mm. However, the gap isn’t too wide. As far as customizability is concerned, there are many amazing handgun options of the 9mm and the 10mm is also available in Glocks. 

Bottom Line

The 9mm is an amazing cartridge that is still the most popular handgun round on the planet after 121 years of its introduction. It is used by militaries, police, and civilians alike. The 9mm is very controllable and small enough to increase the mag capacity of even a sub-compact handgun. 

The 10mm Auto was developed in the ’80s as a powerful round for use by FBI agents. However, it sufficed more prominently as a good tactical round and suitable for hunting game animals. Although at the expense of higher recoil and lesser controllability when compared to the 9mm. 

Each of these rounds has their own place. However, the weight shifts more towards the 9mm in terms of versatility.