The Unappreciated 10mm Auto

glock_29_sf_10mm_bug_out_survival_hunting_gun_pistol_buffalo_boreThe 10mm auto is a fine cartridge that was created as a very real solution to a very real problem. Unfortunately the 10mm performed exactly as designed while predictable humans went and messed it all up. But before we start, if you are quite familiar with the 10mm auto and perhaps even happily own one, you likely live in Montana, Wyoming, Idaho, Alaska or Texas. According to a contact at Smith & Wesson, the vast majority of 10s are sold in those states and thusly the vast majority of appreciation for the 10mm is found on those vast states. By the way, if you add up the entire populations of MT, WY, ID and AK, it is still less than one-sixth that of Texas.

Revolvers these days seem to jump from .22 to .357 without so much as changing shelves in the gun store. And then they go up from there to .41, .44 Mag, and onto the wrist-snapping .454, .460, .480, and a choice of .500s. While pistol cartridges, on the other hand, look like a bunch of inbreeds sharing the same clothes and bald heads. In fact it can be comical debating the differences between the .380 through the .40 like little kids acting tough in the sandbox. The .45 struts around like the big man on campus, but is actually just an old guy driving a sportscar. And then there is the 10mm looking like the giant blond Russian villain in a Bond movie. A huge side of beef that can throw a man across the room.

You’re The Man

glock_29_sf_10mm_bug_out_survival_hunting_gun_pistol_cooper_bookJeff Cooper was instrumental in the design of the 10mm and as a .45 fanatic, Cooper’s standards, while socially abrasive, were high, and the 10mm reflects that quest for handgun perfection (yes, that’s a not-so-subtle nod to Glock). The original 10mm produced over 600 pounds of energy by firing a 170 grain jacketed hollow point at 1300 feet per second. For reference, a Buffalo Bore +P+ 9mm can generate about 500 ft-lbs of energy with a 115 grain bullet at 1400 fps (if your gun can handle it), while regular 9mm loads often carry less than 300 ft-lbs of energy.

Related: The Art of the Rifle by Jeff Cooper

But for further reference, stuff some Buffalo Bore 155 grain into your 10mm and you can easily get 774 ft-lbs of energy. Even the 220 grain hard-cast bullet bear loads I use in my 10mm scream along at 1200 feet per second and still exceed 700 ft-lbs of energy.  And that’s out of a gun not much bigger than my subcompact Glock 26!

Related: The Katrina Pistol

To handle a real 10mm cartridge (not that watered down FBI stuff) a new gun was needed and the Bren Ten was born. Unfortunately health problems prevented the Bren Ten from reaching puberty, heck it didn’t even reach kindergarten before going bankrupt, but in it’s short life it did become a meme for Miami cops just like the 24-hour five-O’clock shadow. However, the genie of autopistol power was out of the bottle. On a side note, the actual Bren Ten used on the Miami Vice TV show shot .45 blanks and was heavily chromed to show up better in low light scenes.

The generally accepted demise of the 10mm’s popularity is from a recoil level that is certainly more than the 9mm that many LEOs were qualifying with. The FBI was all hot and heavy for the 10mm when it arrived on the scene, and it is easy to imagine why the serious government shooters would be excited about what the 10mm offered. But for the vast majority of special agents and desk jockeys who draw down on paper as rarely as possible, the 10mm felt like Dirty Harry’s hand cannon. And don’t get them started on follow-up shots.

There was also another issue at work to shove the FBI in the direction of the .40 S&W and that was flat-out pistol durability. The 10mm is a much hotter load and all that bang takes it’s toll on hardware. Machining and metallurgy at the time was about as good as the music from the 1980s. But there were some winners in that decade with Guns N Roses and Glock among them. Unfortunately Smith & Wesson was not one of them. Smith produced a pistol named the 1076 and nicknamed the “FBI Pistol” after the bureau placed an order for 10,000 of them. But it only took 2400 of the pistols to arrive before the FBI canceled the order and moved on.

Tap Twice, They’re Small

glock_29_sf_10mm_bug_out_survival_hunting_gun_pistol_compare_9mmThe initial attempts to dilute the 10mm cartridge into something you could drink all day long punched a hole in the auto-cartridge lineup. And the .40 S&W stepped in and saved the day. Or so we thought. Today the difference between a 9mm and a .40 is minor in the big picture, but the difference between a 10mm and everything less than a 10mm is significant. Not only does the 10mm punch much harder, but also carries that energy far down range. So much so that a real 10mm (not that wimpy FBI stuff in the white box) has more umph at 100 yards than a .45 has at the muzzle. Even more, if you walked into a bar, the 10mm would be drinking beer with the .357/.44 magnum crowd rather than with the parabellum and its friends sipping cocktails. In fact, the 10mm routinely beats the .357 in arm wrestling, and often ties with the .41 Mag.

Is That Real?

If you saw a foot-and-a-half long auto pistol with a bore big enough to plug with your finger sitting in the display case at the gun store, you’d probably think it was a fake handgun, or at least a one-off custom job. And it’s true that autopistol designs present very real limits on cartridge size and design, but that’s no reason to throw out a perfectly good caliber just because the Feds found it a little too snappy for their manicured hands.

Related: Project Squirrel Gun

The two things the 10mm has over the smaller rimless cartridges is a longer case and a bigger bullet. The larger case holds enough powder to launch 200 grains of lead over 1200 feet per second, and light rounds at over 2400 FPS! That’s rifle territory. So with the right driver behind the wheel, er I mean slide, the 10mm is a serious deer hunting round coming out the chute of an auto-pistol that some choose to carry inside their waistband.

For decades, the .357 was the minimum gun in black bear country and the .44 Mag at the bottom of the list for trespassing on grizzly land, especially in Alaska where everything really is bigger. So when you reduce bullets to numbers, the 10mm puts some outstanding points on the board. Delivering over 600 foot pounds of energy was Cooper’s goal for his super cartridge. You can always downshift the powder load or bullet weight for lesser tasks, but you cannot put more power where it won’t fit. History recorded that the 10mm was uncomfortable to shoot by the average G-men and G-women. So while the 10s were being emasculated leading to the so-called “FBI Load,” the .40 S&W jumped in bed with the Fibs. Before we knew it, the 10mm auto was a footnote and if it wasn’t for a rabid constituency of 10-lovers, it would have died. Luckily Colt Firearms was one of those 10-lovers and produced the Delta Elite in 1987. The Delta Elite was a 1911-esque design that surely pleased Jeff Cooper who probably appreciated the 1911 in .45 more than Browning himself.

Colt to the Rescue

glock_29_sf_10mm_bug_out_survival_hunting_gun_pistol_billboardThe Delta Elite is considered the first successful 10mm pistol but slow sales stopped production in 1996. Then at the 2008 SHOT Show, Colt announced the Delta Elite in 10mm would return. Overlapping the Colt timeline, Glock produced its first 10mm in 1990, a large frame named the Glock 20. But in a twist of fate, the Glock 22 (.40 S&W) was released first because the FBI flip-flop from 10mm to .40 S&W thus back-burnering the 20 for a few months. Six years later in 1996, the subcompact 10mm named the Glock 29 was released into the wild. And today there are two 29s (Gen4 and SF) along with a new long-slide MOS version named the G40. So in case you lost count, your local gun store could carry four distinct versions of Glocks in 10mm. And there are at least half-a-dozen other major manufactures producing 10mm pistols as well.

Ten is the New Ten

bear_countryToday, the cult-like following of the 10mm is being replaced by the mature appreciation of the cartridge that Colonel Cooper wanted. 10mm ammo is plentiful with bullets for self-defense, big game hunting, and even hard-cast bullets for the most dangerous animals in North America including grizzly and polar bears. It should be obvious that if your stable of survival-oriented handguns has increased beyond the traditions, them give serious consideration to the 10mm auto. In fact, think long and hard about the 10mm as a single solution for both defense and hunting when the World goes all ROL on you. And for the record, I think of Glocks like food storage; more is better and I don’t get rid of the old just because I got something newer.

Related: Glock 42 Review

Being essentially a .40 Magnum, the 10mm auto has changed from a choice between pain or power, into a fighting man’s cartridge that has the respectable knockdown energy and flat trajectory that lesser rounds can only dream of. So like the rattlesnake, yes it bites, but those new to the 10mm most likely just misunderstand it. And that is all about to change…again.







Doc Montana
Written by Doc Montana

Doc honed his survival skills through professional courses, training, and plenty of real-world situations, both intentional and not. Doc lives to mountaineer, rock climb, trail run, hunt, race mountain bikes, ski, hunt, and fish. Doc Montana holds PhD’s in both Science Education and Computer Science and currently teaches at a University in the northern United States. Read his full interview here. Read more of Doc's articles.

21 thoughts on “The Unappreciated 10mm Auto”

  1. Excellent right up there Doc Montana, I couldn't have said it any better.
    I'm a big fan on the 10 mm auto cartridge.
    When it comes to shooting handguns, I shoot my Glock 20 more often than any other handgun these days.
    I used to shoot a lot of 9mm/9×19 ammo, not anymore, the 10 mm auto is my go to handgun calibre.
    My Sig-P210-6 in 9mm is becoming a safe queen these days. LOL.
    Long live the 10mm auto cartridge, it deserves more credit than the 40 S&W which I call ( short & weak ).

    • Thanks for the read SIG. I learned to savor each and every shot when .22 ammo went into long term hibernation. Seems a generation or two of shooters cut their teeth on mag dumps so cost per round downrange is a major metric in pistoling. And that is one reason I recommend teaching youth to shoot bolts early on and work through the foundations of shooting from start to finish with each shot.

      Carrying that philosophy forward allows a shooter to enjoy and learn from each shot so sitting on top of a full mag produces the same experiences as a near-empty one. Add some stiff recoil and the shooter can learn the same with fewer rounds. Well, except when you need to practice sustained cover fire. But I don't endorse the 10mm for that use. The 9mm shines with ultra-high cap mags.

      On a side note, to assist in appreciating each shot, rather than cleaning out my mags at the end of a shooting session by shooting them dry, when I stop, I stop and unload all the mags into a plastic container. Needless to say, the container contains a variety of different rounds from .22 to 12GA. It rarely amounts to much but it does add up to a full mag or two every half-dozen range trips.

  2. Interesting read, thanks for writing it up! I think the 10mm is severely underappreciated in its capability – especially as a SHTF type gun. However, it has a couple things going against it: cost and availability of ammunition, and stiff recoil. In a day where the trend is to ditch the big-bore guns and snap up a 9mm for extra firepower and quick follow-up shots, the full-tilt 10mm is a magnum in everything but name…and fast follow-up shots can be tough with max loads. Having had Glock 20s and 29s, and lots of experience with Delta Elites and Smith 1006s, 1066s, and 1076s, I can tell you there is a reason for the intermediate-power 10mm loads the FBI mandated. But for seasoned shooters who are experienced with controlling recoil, the 10mm definitely offers extreme firepower and horsepower, especially when coupled with a Glock 20 or 29.

    • Hi Drew. Thanks for the read.

      Our local stores have plenty of 10mm ammo options with the cost more in line with revolver cartridge prices, not auto ones. At least not of the 9mm variety.

      Regarding followup shots, the shot split time difference is measured in seconds or tenths of seconds, not hundredths of seconds. Or thousandths of a second if your name is Jerry.

      Regarding recoil and big game that gets a little too close, every gun has exactly the same recoil before it's fired. In other words, the recoil happens after the shot so in many CQBs in the wilderness rarely afford time for a second shot. At least before the attack. So what comes into play becomes 1) you have to have the gun with you, 2) you have to be able to quickly draw the gun, 3) you have to be able to aim the gun, and 4) you have to be able to fire the gun a split second after the draw and aim. Only then does the recoil matter. But trust me, you won't be thinking about recoil at that moment.

      In the survival community, there is a fondness for leaning personal preps towards those of the alphabet agencies. However most survival situations require a reversal of roles where the citizen is running from the fight while the alphabet is running towards it. The engagement strategy has similarities except retreat is not at the top of the FBIs list of acceptable responses to the situation. If you are bugging out and/or hunting with your 10mm, you will not be prepared for a thousand-round firefight while waiting for armored reinforcement and helicopters. That's just a fact of life.

      The 10mm Glock I use is the 29SF (short frame). It does have a short length grip keeping it small, but even my big mitts can hang on to the 29 especially with the Pierce pinky extension. And if you look at the pics, you will see the rest of the mags are the full 15 round ones for the Glock 20. Using the longer mags provides a near-full sized grip so the barrel is the only short part of the gun at that point. Plus the tiny difference in backstop to trigger distance with the SF version gives a slightly better hand wrap (IMHO) compared to the regular frame.

  3. Instead of getting into the weeds I will attempt to explain with logic that 10MM requires much more training and money to master.

    Carbines are not kissing cousins to the pistol in any way shape or form and ergonomically is just one another is the sight to bore height bullet drop it matters little difference in caliber both are in,

    the sight for a carbine needs to be a bullet drop design or else a lot of misses here is the bullet drop
    10MM 180 grn 16" carbine
    Path in inches
    -1.5……. 0.0…. -5.0..-17.8

    Consider a carbine is higher velocity than a 4" pistol by about 200 to 300 FPS
    Somewhere in there is a lot of misses of head size objects especially if the operator does not do some mental gymnastics as to range and use the proper bar SWING AND A MISS. you do not have think too hard to figure 15.5 inch difference and now consider the differences between the pistol & rifle bullet drop so if your not on your toes you'll be off add in a imperfect aim by 1 MOA and it gets worse from there.

    Common ammo great but you better do the training to assure both are on target and you can under pressure hit the X-ring every time all the time.

    I still like to see a case of ammo on any shelf OR buy and store cases and until trigger time evaluates the ammo you choose will function accurately in both carbine and pistol.

  4. My hat hangs in missoula. With that geographical location, I found myself urban and shortly thereafter in bear country. At the time my glock 17, or 26 were my constant companion. I resolved to put together a glock 29 capable of reliably launching the buffalo bore 220 gr. Hardcaste. I purchased a wolf 23 pound recoil/slide spring, as well as a wolf drop in barrel. I proceeded to shoot 200 rounds of sig 10mm 180 gr. For breaking in. I then proceeded to shoot 3 boxes of buffalo bore with dismal reliability issues. 3 to 4 rds / mag were failing to feed. Ive tried everything except mag springs. Another thing I found was the sig fmj was penetrating consistently deeper than my buffalo bores. I shot into stacked 2×6 and the sig rds penetrated 1 1/2'' deeper every time. So for now im sticking withe sigs 180 gr.fmj At 1200 fps for my carry round. Doc do you have any suggestions for my 29 to digest 220s ? Also am I missing something with the fmj sig doing better against a heavier and hotter round? Thanks for the interesting read.

    • Hi HDL,

      Buffalo Bore is a local company, formally St. Ignatius, now Salmon, ID. Another heavy round you might want to give a shot is Underwood. It's not without risks however as noted in this high profile failure:

      Did you try your factory barrel? I've also noticed that some BB hard cast bullets might need bit of polishing. They do have sharp corners, but also some mild scuffing.

      The G29 has always had the double spring that was only added to the rest of the Gen4 lineup recently. I've seen no need to replace/upgrade it. But then I don't shoot my 10 all that often nor for any sustained amount when I do. But it still gets much more of a workout than my Ruger Alaskan.

      My guess on the speed of the SIGs is that they might have a faster burning powder that can accelerate the bullet in a shorter barrel. I don't think Tim at BB does much with the 29 so his BB ammo might still be burning powder when the hard cast runs out of barrel. SIG has a vested interest in shorter barrels while Tim likes long barrel Super Redhawks.

  5. Thanks for the read.

    Shooting any pistol at a 100 yards requires ballistic integrity and compensation. And certainly rifles lob bullets many percent differently from those tubes with wheels or slides. But that's not my point. Once dialed in (what you call training and money) the 10mm is a producer of the highest accord.

    I think the 10 suffers from not having a rim nor a suffix in its name like magnum. But time will tell whether or not the modern centimeter cartridge gains the necessary traction to become indispensable. In my kit, however, it has already proved itself, and coast along in the holster as far as I'm concerned.

  6. The 10mm cost about 3 1/2 times more than 9mm in my area for factory bought ammo.
    9mm about $16 a box of 50 rds. 10mm about $50-55 a box of 50 rds plus taxes.
    I can see why the 10mm is not as popular as 9mm when it comes to paying for ammo.
    Most folks don't have a budget to afford 10mm ammo, compared to 9mm.
    The only reason I can afford 10mm ammo is that I reload my own ammo.
    Other I wouldn't be shooting the 10mm.
    I'm hoping that the 10mm gets more popular in Canada, then the cost of the factory ammo would come down.
    Time will tell how the 10mm will do in the future.

    • Ouch SIG! Around here I can buy 50 round boxes of 10mm for $18 and up. The sixty buck stuff is on the shelf as well and there are plenty of $20 and $30 boxes of 20 rounds, mostly for personal defense. The heavy bullet rounds like BB cost around a buck and a half per round. has options under $30 for 50 rounds starting at $15 for 50 frangible 125gr bullets. The first Remington clocks in at $25 for 50. I guess that is near 3x the 9mm price but that would have to be a Black Friday sale around here.

      I think there is a resurgence in the 10mm, possibly because the 9mm is regaining stature for self defense and LEO carry which makes the difference between the 9 and the 10 more dramatic than when the the .40 is in the mix. So by comparing other close calibers, like .41 and .44, owning both is a stretch, but if you trade your.41 in for a .357, then the .44 seems like a good addition.

      Just a thought.

      • Canadians are always paying a higher price for everything.
        Not just firearms & ammo that are more expensive in Canada.
        Everything is more expensive food, clothing, gasoline, cars etc etc.
        Americans don't know how good they have it, when it comes to paying for products & services.
        You average house in a city in Canada, one would be paying $800,000 to 1 million easy these days.
        Even condos in the city like Vancouver or Toronto they start at a million dollars for a 600-800 square foot condo.
        I've seen 1200 square feet condos in a wealthy neighbourhoods selling for 2.5 million & more.
        It's very hard if not impossible for a young family to get a place in the city these days.
        Canadians pay a heavy price & get the shaft up the ass & most smile & say thank you with open arms. LOL .

    • Yes I've heard of them.
      One of my members at the club owns one, & ive shot it a few times.
      Draw back, they only have 8 round mags, to me that's a thumbs down in my books.

    • Not much of an EAA fan. Weird ads and a hit-and-miss reputation. But most of all, I prefer the Glock manual of arms.

      On a side note, got a quick contest: Who can be the first to correctly identify the cartridge holding up the Glock in the picture above with Cooper's book?

      • It's certainly not a handgun cartridge that's holding the glock up.
        I'd say a 30-30 Winchester.
        With out seeing the whole cartridge in the picture.

      • Okay, I'll take a guess. Trying to judge from the length of the neck and possible diameter (guessing from how much of the opening of the trigger guard it is filling up). Looks like bigger diameter than a .375 H&H, and too much taper to be one of the .458s (Win or Lott) so my guess is.460 Weatherby Magnum!

        • We have a Winner!

          Yes, the cartridge is the .460 Weatherby Magnum.

          The Weatherby .460 mag was the world's most powerful commercial cartridge for almost three decades until 1988 when the H&H .700 Nitro Express topped it.

          For reference, the .460 generates well over ten times the muzzle energy of the 10mm. In fact at 500 yards, the .460 can still carry over five times the energy of the 10mm at the muzzle.

          Another way to look at it is that the cost of the Glock is about the same as three 20-round boxes of .460 ammo.

          Good eyes L P. Knowing your way around the big bores, the really big bores does keep things in perspective.

  7. I purchased a High-Point 10mm carbine in March of 2018. It was the only way for me to get a 10mm in my very limited price range. Having fired every caliber carbine they make, I bought the 4590, in 45acp, and the 1090 in 10mm. While the pistols get a bad rap, I have had great success with the carbine's. A great bang for buck ratio in my view, ammo is a little limited in my area. Even then, I can get 180gr hp rounds for $16.00/50 round box, by PPU,S&B mostly FMJ) or 20 rounds of Hornady for $1/ round. The 10mm quickly became my go to gun, and will take down any animal in my area, as well as legal to deer hunt with. At 100 yards, I can keep 1.25 inch groups with the factory iron sights 9 of 10 mags. Love it, and very happy to see 10mm making a comeback!


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