10mm Ammunition: 7 Things You Need to Know

Tom McHale hurts our brain with more info about 10mm ammunition than you probably need to know.

A family of Sig Sauer V-Crowns, left to right: 9mm 124-grain, .40 S&W 180-grain, 10mm 180-grain, .45 ACP 230-grain.
A family of Sig Sauer V-Crowns, left to right: 9mm 124-grain, .40 S&W 180-grain, 10mm 180-grain, .45 ACP 230-grain.

USA – -(AmmoLand.com)- For the past month or so I’ve been tinkering with a 10mm pistol, the Springfield Armory 1911 Range Officer Elite. It’s a beautiful handgun that’s made special by its caliber choice of 10mm. Roughly equivalent in ballistics to the lower end of .41 Magnum, and more powerful than the tried and true.357, it’s an interesting option for a carry gun.

The 10mm shares case diameter with the .40 Smith & Wesson, so in theory, pistol capacity can be the same in a double-stack design. The 10mm is a bit longer, so grip size circumference has to be bigger than that for other calibers like 9mm and .40.

10 mm Ammo Boom Factor

For carry or home defense use, the most common loading for 10mm ammunition will be a 180-grain projectile. I tested a pile of the excellent Sig Sauer V-Crown from a Springfield Armory 1911 Range Officer Elite and measured average actual velocity of 1,186.3 feet per second. That translates to muzzle energy of an impressive 562.6 foot-pounds – a good 150% more than most 9mm or .45 ACP loads.

Here's an interesting option from Doubletap Ammunition - a 200-grain hardcast load.
Here’s an interesting 10mm ammo option from Doubletap Ammunition – a 200-grain hardcast load.

Of course, if you want to go with different bullet weights, you can find some interesting options too. For example, the Doubletap Ammunition 135-grain Controlled-Expansion bullet left the same Range Officer Elite pistol at near warp speed of 1,494.3 feet per second. That speed cranked up muzzle energy to 669.5 foot-pounds.

If you’re in the more is better crowd, Doubletap also makes 190-grain Equalizer load that fires two projectiles from each case: a 135-grain JHP and a 95-grain lead ball. Ouch.

Combo Carry and Outdoors Caliber

If you are worried about grizzlies, like Dean Weingarten is, I’d choose an MK-19 Automatic Grenade Launcher over any pistol caliber. However, I’ve not yet found a comfortable holster for that beast. If you plan to carry a pistol in town and out in the woods, 10mm isn’t a bad option.

For outdoor use, consider some of the more interesting ammo from Doubletap Ammunition. They make a 10mm round that packs a wallop with a 200-grain hardcast lead bullet; When I tested it, it chronographed at an average of 1,132 feet per second. That’s 569.84 foot-pounds of kinetic energy and serious penetration considering the hardcast bullet ballistics.


Pondering the recoil factor subjectively, I don’t notice much difference between the .45 ACP and the 10mm when fired in similar pistols. Neither are causing temporary PTSD, but then again, I’m shooting both calibers from full-size, all steel pistols. For the .45 ACP, I shoot a Springfield Armory 1911 TRP which weighs in at 2.63 pounds empty. For 10mm, I’ve been testing a Springfield Armory 1911 Range Officer Elite which tips the scales at 2.56 pounds empty. Obviously, these are weighty pistols so perceived recoil is mitigated – a lot.

I've been shooting a variety of 10mm ammo through a full-size and heavy pistol - the Springfield Armory 1911 Range Officer Elite.
I’ve been shooting a variety of 10mm ammo through a full-size and heavy pistol – the Springfield Armory 1911 Range Officer Elite.

If we do some quick recoil math and run the numbers for each using an “average” load and the weight of each pistol, the 10mm shows a bit more energy. The .45 ACP TRP firing a 230-grain bullet at 880 feet per second generates 5.43 foot-pounds of energy. The 10mm Range Officer Elite firing a 180-grain bullet at 1,181 feet per second delivers 6.28 foot-pounds. It’s more, but not a night and day comparison. To put those numbers in perspective, a lighter pistol like the .45 ACP Springfield Armory XD-S socks you with 8.15 foot-pounds of recoil energy. So, taken in context, if you’re cool with a .45, a 10mm isn’t going to make you run for your safe space.

Just for kicks, I ran the recoil math on a couple of 9mm pistols too. Since the lighter weight polymer pistols increase the felt recoil number, the results are a bit surprising. When firing a Glock 26 Gen 4 with 124-grain 9mm bullets moving at 1,151.5 feet per second, you’ll catch 5.43 foot-pounds of recoil energy. Even the larger and heavier Glock 17 Gen 4 will deliver 5.65 foot-pounds of recoil energy thanks in part to higher velocity generated from its longer barrel.

Invention: A Cartridge and Pistol Pairing

Back in 1979, two guys, Thomas Dornaus and Michael Dixon, wanted to make a bigger semi-auto pistol that exceeded the performance of the .357 Magnum while offering the capacity and fast reload benefits of semi-automatic pistols.

Around the same time, Colonel Jeff Cooper was jonesing for a new pistol and cartridge combination, which he called the .40 Special. A working partnership led to Cooper providing insight and design ideas and Dornaus and Dixon handling engineering and manufacturing. The prototype pistol from this effort, based on a beefed up and redesigned CZ-75 was called the Combat Service Pistol (CSP) 80. One thing led to another, and before long the new pistol was deemed the Bren Ten and the cartridge the 10mm Auto. The pair manufactured the pistols from 1983 to 1986, but rush-to-market quality issues doomed the effort.


After the infamous 1986 Miami Shootout, the FBI embarked on a search for a more powerful handgun alternative that would penetrate more consistently to incapacitation depth.

While the case diameters are identical, the length is dramatically different between the .40 S&W (left) and 10mm (right)
While the case diameters are identical, the length is dramatically different between the .40 S&W (left) and 10mm (right)

After lots of bickering and testing, the agency standardized on the 10mm in 1989. Sort of. The final ammo product was issued to Special Agents carrying the Smith & Wesson 1076 pistol. The 10mm Fed affair didn’t last long as the recoil was a bit stiff and the pistol size too large to meet the agency objective of standardizing on a single handgun for everyone. Oh, and the 10mm ammo was more like a 10mm minus. The FBI wanted the cartridges downloaded to fire a 180-grain bullet at 950 feet per second instead of the full 10mm velocity spec.

Before too long, someone noticed that a downloaded 10mm case had extra interior space for rent and the shorter .40 S&W was born. The rest is history. We should note that the movement to .40 S&W wasn’t entirely because of recoil. The longer 10mm case requires a larger pistol, and those with smaller hands had trouble reaching the trigger with proper leverage to fire in double action mode.


Reloading for the 10mm is easy. Reloading for the 10mm is a royal pain in the @ss. It’s easy because both cases and bullets are large and easy to handle. There are plenty of projectile options in .40 caliber, so it’s easy to find components. Reloading is a royal pain because the brass is so similar to .40 S&W. Actually, it’s virtually identical except for the length. Try sorting through a pile of mixed range pickups and see how much fun it is to find the 10mm cases.


The 10mm shares bullet and case diameter with the .40 S&W. Both use a .400-inch diameter projectile. The case is also nearly identical with the exception of length. The 10mm parent case is a .30 Remington while the .40 S&W parent case is a… 10mm. No big surprise there. Both have diameters that start at .425 inches at the base and narrow to .423 inches at the case mouth. The big difference is that the 10mm case is .992 inches long while the .40 S&W empty case measures .850 inches. When loaded with a projectile, those figures translate to maximum overall cartridge lengths of 1.250 inches for 10mm and 1.135 inches for .40 S&W. It doesn’t sound like much, but when you’re trying to design a pistol grip fits all hand sizes, that extra distance required makes things tricky.

Left to right: Sig Sauer 180-grain FMJ, Sig Sauer 180-grain V-Crown, and Doubletap 200-grain hardcast.
Left to right: Sig Sauer 180-grain FMJ, Sig Sauer 180-grain V-Crown, and Doubletap 200-grain hardcast.

Is it Better Than…?

Guess what? Whether it’s better than 9mm, .40 S&W, 45 ACP, .357 Sig, or .38 Super is irrelevant. It would be a boring world, indeed if we were all limited to the one “best” choice. How utterly miserable life would be if we only had one type of pickup truck, lawn tractor, 80s band, or Chia Pet character? Do you like it? Does it do the job you want it to? If so, go for it.


Tom McHale is the author of the Practical Guides book series that guides new and experienced shooters alike in a fun, approachable, and practical way. His books are available in print and eBook format on Amazon. You can also find him on Facebook, Twitter, Instagram, and Pinterest.

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The FBI is still using the 10mm, but only in the MP5 (we collected their empties at the local range for years). We refer to the .40 S&W (short & weak) as the FBI Pussy round as they couldn’t handle the recoil as it “hurt their widdle wists” so went to something less manly.


Have a Walther 40, a Kimber 10 and a Tanfoglio 45. All are excellent firearms and will do what you intend for them to do.

Alan in NH

+I have a Glock 10mm long slide model 40. Sure it’s got the plastic [adjustable] sights but a 3.5# trigger. I saw a guy on YouTube shooting .40 S&W ammo through his, so I thought about it for a while and when I thought about it long enough, I loaded the magazine with 15 rounds. I figured it would either work or it wouldn’t. They all fired and ejected normally like it was made that way no problems. It’s good to know that is an option Glocks are amazing. try that with your Kimber.


Someone needs a new calculator. More than 150% ???? Really? Maybe compared to 22LR. The ft-lbs that you are showing are maybe 20% greater than a .40S&W of the same bullet weight. Seriously. Such an outlandish calculation error is beyond believable, even by the liberal MSM. . . . . Uh, well, depends on who is making the outlandish calculation I guess. . . . . . . .


Here we go again, boasting that the 10mm can be or is equal to the .41 Magnum. That dog just don’t hunt. As any handloader of the .41 Magnum can tell you, you’d have to load the .41 Mag “down” to get to 10mm Ballistics. If you load the 10mm and the .357 Magnum to their full potential you’ll find they are pretty similar in terms of energy while same weight .357 Magnum bullets have higher sectional density; a key component in penetration. Why don’t we advocate for the 10mm for what it can do, not what it can’t. The… Read more »

Wild Bill

@57K, You sound like a reloader, so I am going to ask you if I can use a .380 caliber (.355 diameter) bullet in a .357 case. Will the crimp take care of that .002 difference? I want to use a .355 bullet with a .357 load to obtain a flatter trajectory. What are your thoughts?


I have done it – it works. But you will probably be happier with the 110gr 357 bullets cuz you will need the crimp grove.

Wild Bill

@Cat, I want to use Ramshot Enforcer for powder, and a .380 caliber, 65 grain (no lead, all copper projectile that I found at Midway), .355 diameter for the projectile. If I full size the .357 cartridge case, can I get away with not crimping the .355 bullet?


I would like to see a S&W M&P 2.0 10mm to give the Springfield XDM 10mm some competition. I think S&W took a good step with the 610 again, but falls short with a lighter weight auto package.


.45 Super gives similar ballistics and doesn’t take a new and expensive gun, just different springs and extractor tuning! Underwood .45 Super
255 gr hardcast 654 ft/lbs
230 gr hollowpt 616 ft/lbs
200 gr penetrator 517 ft/lbs
185 gr hollowpt 694 ft/lbs
170 controlled fracture 590 ft/lbs
120 gr defender 682 ft/ibs

What’s not to like- no new gun, hunting or defense too


When WE retired from South Florida to East Tennessee last winter, I was looking forward to perhaps partaking in some hiking the Appalachian Trail and other outdoor activities. I discovered however, that I’m no longer in “Infantry shape” and thus I have taken up Trout fishing. Regardless, I now live in Bear country. Within the first 5 weeks we were in our new home we sighted a very healthy coyote and a juvenile mountain lion within 30 meters of our backyard but just outside the fence. So being the NRA INSTRUCTOR that I am, I wanted a good caliber that… Read more »

Will Flatt

I want one just because I think 10mm has that cool factor that – for the indefinite future – won’t go away. I already love .40, so I guess my next pistol is going to be the 10mm. Now all I have to do is figure out which brand and model; that will be a challenge now that so many outfits are offering it!!


The 40 Short and Weak is the answer to the question nobody asked. It has been a huge flop in law enforcement circles. Witness the fact that the seminal law enforcement agency leading the pack that is the FBI has dropped it and huge numbers of state and local agencies followed suit. I’ve owned three forties, two Glocks and one Kel Tec folding carbine. Sold them all. They generate significant muzzle jump, even in the Glock which has one of the lowest bore axis ratios in the industry. The only way to compensate for that is to… well, COMPENSATE the… Read more »


Jim_K: I’ll play nice and not write what I’m thinking. So I’ll leave it at: LOL!


Love it! The article and the 10MM. Now get one!!!