Cartridge of the Week, the 10mm, 10mm Auto

Those who have followed my posts know I have one foot in the past and one barely in the present when it comes to firearms and cartridges. It takes a lot of evidence and time to prove something to me. Nothing like the tried, true and tested. Nevertheless, I cannot argue with the point that somethings are good right out of the box, like the Colt Python, wait there I go again. Another thing that is hard to argue with is physics. Well you can, but people will see you talking to yourself and runaway. When it comes to physics and raw proof, there are few cartridges that rival the mighty 10mm Auto.

The 10mm Auto

The 10mm Auto cartridge was thrust into service due to the death of two FBI agents on April 11, 1986. On that date FBI agents, engaged in a firefight on the streets of Miami with two serial bank robbers and killers. An assailant wielding a Ruger Mini 14 .223 semi auto rifle killed special agents Jerry Dove and Ben Grogan. The glaring problem was that an assailant, Michael Platt, was already shot approximately nine times including a wound from a 9mm that broke his arm and lodged in his chest cavity. This round collapsed a lung and filled his chest cavity with blood yet he was still able to fight and kill two agents.

FBI Special Agents Jerry Dove and Ben Grogan

One suspect, William Matrix, took six shots to succumb to his wounds. Platt took at least 12 shots to bring to an end his actions and his life. Of the eight agents who engaged the suspects, only one was uninjured. Seven were either shot multiple times, injured by shrapnel from bullet impacts, and as stated above two killed. All this after the suspects had been shot multiple times. The guns used by the agents were wheel gun .38 Special .357 magnums, 12 gauge shotguns and 9mm semi auto pistols. Tactically some mistakes were made in the stop but that is only half the story. It should be noted, that the suspects had no drugs in their system.

The result of this event, and later the North Hollywood shootout, would result in at least three major changes in the law enforcement community. The first was the exit of the revolver from the duty belt. This gun had served well but the firepower–amount of bullets that can be fire–had to be changed. Second change, the caliber that most departments used needed an upgrade. Finally, the officers and agents on the front lines needed a caliber as good if not better than the bad guys.

Within a year, the FBI was at work finding the right cartridge. Tests performed on various clothing, barriers, and ballistic gel types resulted in at least three outcomes. It must create quick incapacitation by damaging the central nerve system. It must cause the greatest amount of internal injuries to cause massive blood loss. Twelve to 18 inches of penetration must be achieved and with good bullet expansion.

Coming Soon to CTD – Rock Island 10mm

The goal was to find a cartridge with better external ballistics than the .45 ACP and better terminal ballistics than the 9mm Parabellum. The search resulted in the 10mm Auto designed by a legend in the firearms industry, Jeff Cooper. The 10mm was on the shelves at least four years prior to the Miami tragedy. Of the cartridges tested the 10mm was vastly superior to the 9mm in exterior and terminal ballistics. As far as the .45 ACPs performance, the 10mm’s external ballistics performed well above the .45 ACP. However, in the terminal ballistics it was just marginally better.

Unfortunately, when it came to the internal ballistics the 10mm, it was a third-place finisher. The 10mm’s pressures and subsequent recoil made it a little too hard to tame in a firearm that could contain numerous rounds and adequately wielded by the majority of agents. Some female agents, officers and those with smaller hands and body frames had trouble controlling this monster round. The FBI experimented with a 10mm light at this point. This defeated the purpose and only created a somewhat inept .45 ACP.

Sadly enough the FBI and other agencies ran away too soon from the 10mm Auto. They did so not because this is a bad cartridge, only that a better one was found for their purposes. That cartridge was, and continues to be, the .40 S&W. The .40 has taken the law enforcement community by storm and rightly so, it is a great round. Nevertheless, the 10mm still has a place in that community. It is a great cartridge and for those who can handle what it comes wrapped in and the bark that goes with the bite, it is everything the .40 S&W is just on steroids. As firearms enthusiast we must not let the 10mm Auto go quietly into the night.

10mm Auto – Big Medicine

Have you ever shot the 10mm Auto? What did you think? Let us know in the comments section below!

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Comments (20)

  1. Glock 29SF, 230 grain hard cast lead, 200 grain hp and 180 grain fmj at the range.. I have all the confidence in the world in this round, the gun and my ability to use them effectively.

  2. My 4’9″ wife has no problem with my G20 and I shoot what I leave loaded in it, Winchester Silvertip which are well north of 600 ft.lbs. I also have some DoubleTap ammo that runs well over 700 ft.lbs and that’s also no problem to shoot. A snubby 357 with reasonably stout loads produces a good deal less power and is a lot less pleasant to shoot. In 15 years I think I’ve had three failures in my G20, all of them were bad reloads, the cheap ammo at a local range.

  3. Thank you all for posting your stories, opinions and statements. I am a 10mm lover because of my cousin (Delta elite) and my grandfather (who had several different handguns) the 10mm is still used on big game hunts with only a few alternate choices such as a 41, 44 magnum etc.

    Keep up the good work!

  4. I own two 10mm guns. A STI Perfect 10 and a Glock 29SF. I think a good comparison is the 6″ Perfect 10 using 155 gr. Hornady Custom XTP ammo shoots 100 fps faster than my Ruger GP100 6″ .357 mag using Hornady 158 gr. XTP. Roughly 1,400 fps vs. roughly 1,300 fps on my chronograph. That is a lot of energy. They are both extremely accurate guns. The main difference is that the Perfect 10 holds 14+1 with the factory mag, and 17+1 with the optional mag. I will take the 10mm over any other pistol cartridge. The kick is not bad, and the smile is big. The cheapest 180gr 10mm ammo shoots over 1,100 fps. The shorty Glock 29SF slows things down by about 100-200 fps depending on ammo. It also holds 17+1 using a Glock 20 mag with +2 extension. Don’t compare 10mm to .40 S&W. Compare it to a .357 mag, but the 10mm carries 3 time the ammo. Ammo cost is similar to .357 mag also.

  5. Doubletap ammo loads .40 S&W with 200 grain bullets @ 1050 FPS for 490 ft.lbs. muzzle energy. I’ve never used anything over 180 grain in my 40 myself though.

  6. Attn:Steve Camp. I do not know where you are getting your info, but it is wrong. The 10mm Auto and the 40 S&W are both a .400 diameter bullet and the 10mm case is .142″ longer than the 40S&W. .992 vs .850. The overall length is also about .142″ longer,depending on the grain bullet you are using. The 10mm Auto uses a large pistol primer and the 40S&W uses a small pistol primer. The 10mm Auto can propel a 200 gr. bullet over 1200/ft.sec. You can’t even load a 40S&W with a 200 gr. bullet,It isn’t safe. I have a S&W 411, Glock 22 and 23 in 40S&W and a Colt Delta Elite and a Glock 20 in 10mm Auto. The felt recoil is noticeably different. I hope this info was helpful.

  7. I am not sure I understand why the 10mm is touted as a better round than the .40S&W
    The .40S&W is .007 bigger than the 10mm. They are similarly shaped. I would think they would be an equal for each other. I mean 7 thousands of an inch is nothing. To put this in perspective… That is less than 2 pieces of paper put together. Now the only thing I can figure is maybe the 10mm has more grains of powder? maybe!! Well if someone could explain why the 10mm is on Steroids compared to the .40S&W I would appreciate it.

    Thanks Guys

  8. Rokurota,
    I am 5’7″ as well and carried a .357 Magnum for many years as a duty weapon. So I am in agreement with you in that we “runts” can shoot the big stuff, and do. However, this was the finding of the FBI and their conclusions which were based on hundreds of candidates not just two bulldogs like you and me.

  9. Why is it always said that “females and small-statured” folks can’t handle the big rounds? Those two aspects have little to do with pistol handling. I am 5’7″ and I love shooting .45s, .40s and .357s. Took a female friend shooting for the first time and she didn’t flinch at all emptying my .357 at paper. On the other hand, a “large-statured male” friend refused to shoot my G19 after a few rounds and stuck with the .22.

    It may be that in the FBI trials, it was the women and smaller folks that had trouble, but don’t tell me women and runts like me are universally recoil-shy. It varies by shooter.

  10. Should have read earlier comments firs I guess. I carry my 10mm daily in a Fobus paddle holster under a shirt not tucked in. The 10mm in it’s original loading was just about equal to the .41 magnum revolver round. Winchester loaded a 175 grain round to 1250 fps. for both calibers. The one I used to first qualify with in my 10mm. I also qualified with it in a 4″ S&W revolver but was not allowed to carry that one either. I have also taken 2 deer hunting and dispatched a car struck deer with these guns.

  11. I received my Glock model 20 (10mm)while working as a part time Police Officer. My Chief signed so I could get a police discount on the gun, but told me it was too powerful to carry on duty. A couple of years after he retired I asked our new chief about carrying it. The new chief said if I could qualify with it I could carry it, so for the last few years before I retired I carried and qualified with my Glock 10mm. I hd to buy my own ammunition to do so though.

  12. The only real handicap this cartridge has is a shortage of available firearms. As far as pounding the weapon, keep in mind that Glock loads the 10MM in a couple of models and handles it well. Pretty any large frame handgun with the right recoil springs can handle this well. If the .40 is great, the 10MM can only be better…

  13. I had the opportunity to put a few hundred 10mm rounds thru an MP5/10. Stout round. A lot more recoil than a 9mm. Too stout for those early S&W pistols as I recall….

  14. The 10mm is becoming more popular. I know a couple co-workers who have bought Glocks in that caliber but then again, they are police. Other then Ted Nugent talking it up I really haven’t heard much else about it.

    You have to figure if it is rare then it is more expensive to shoot. I like the 45acp and that isn’t inexpensive. You can beat the price by reloading but that gets time consuming.

  15. I have a freind that lets me play with his Delta ELITE 10 MM it realy moves the steel and i love the gun. I can’t wait to play some more

  16. You’re probably right Pete, I sure as Hell don’t know anything about it. Being a hunter half my life, I never saw any point in auto loaders, so now that the world is coming to an end on the twenty first, I’m having a crash course. As for a defensive round, I do know you don’t want to hand load, so that benefit would be wasted on me. If we make it past DoomsDay, I do want a .45 acp. I’m thinkin’ the Colt New Agent, the one with no sights, but it would be better if it only held 4 in the magazine, so as to comply with don’t ask, don’t tell, don’t let your gun show. I wear a Colt Agent now, so that may get the hammer bobbed, and smaller grips, and annoy my ankle. Y’all get ready for the rupture!

  17. The 10mm seems to be a relatively little known caliber outside of LE and military use. It’s not that there isn’t civilian access to this caliber, it’s just that it never seemed to gain widespread popularity in this arena. Between the .45 ACP and then the .40 SW my feeling is that there was really not enough time for this caliber to come into its own across the board. In my search for hardware that allowed for the use of a single caliber to participate in competitions I have and used three. The 9mm, 45ACP, and the 10mm. These calibers may be found across a spectrum of weapons manufactures in both pistol and sub- gun platforms. Of these three I have found the 10mm to be the most accurate of the three in either of the platform types. There are several excellent ammunition manufactures that provide a fair selection to choose from. However this round reaches its potential when hand loaded. I don’t know that this caliber will ever become popular like the 9 mm or 45 but I also believe that it won’t fade away into history as others have over time. The 10mm will remain a viable LE and, within a narrow spectrum, military/government caliber and platform but I suspect not much beyond those applications. For what it’s worth………

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