Conceived by brilliant gun experts as a defensive pistol cartridge, the 10mm Auto almost fell into obscurity, but then rose to become hugely popular for outdoorsmen’s pistols, particularly those in dangerous animal country.

Here’s my take on it.


  1. The poor man’s 10mm is a police surplus Glock 22 or 23 with 200 grain hardcast Buffalo Bore or Underwood ammunition. While underpowered compared to those brands 10mm ammo, they produce more energy and increased penetration compared to most run of the mill 10mm produced today.

      • @ nicholas kane

        I think that Mark is saying that a lot of run-of-the-mill 10mm ammo, today, is loaded so that it is barely faster than 40 S&W. Consider this data which I pulled from the MidwayUSA web site:

        40 S&W ballistics:

        Remington Green box – 180 grain. – velocity 1015 fps.
        Winchester White box – 180 grain – velocity 1010 fps.

        Compare with these 10 mm loads:

        Winchester White box – 180 grain – velocity 1080 fps
        PPU Ammo – 180 grain – velocity 1083 fps

        See? The 10 mm loads are only about 50-70 fps faster than the ordinary 40 S&W stuff.

        Now, compare with a couple of 10 mm FULL POWER loads on the market:

        Underwood 180 grain – 1300 fps
        Buffalo Bore 180 grain – 1350 fps

        At least 200+ fps increase in velocity. That is a significant difference.

        Now, one must keep things in perspective. People sometime label 40 S&W as “40 Short and Weak” but, come on! I don’t want to get shot by it. A 180 grain JHP moving at over 1,000 fps is still a powerful load (for a handgun).

        It is just that the people who buy 10 mm handguns do so for MORE POWER a la Tim the Toolman. They feel cheated when they pay for a 10 mm handgun but only get 40 S&W performance with the run-of-the-mill ammo on the market.

  2. Excellent article! If I remember correctly, Colonel Cooper wrote that he wanted the Bren Ten so he could reach out to fifty yards with it. Later he realized he should use a rifle for a threat fifty yards away. Twenty-five yards is the maximum sensible distance for shooting handguns at threats. Long distance handgun shooting is a stunt.

    We have a bewildering number of cartridges out there, but that is a sign of our wealth. Better too many, than too few.

  3. Outstanding work Mas, truly.
    I have carried the Glock 40 but just replaced it with the Sig P320 XTEN carry comp in 10mm. I’m not a Glock fan, just don’t trust myself with that light trigger and no safety. DA/SA guy since the 90’s. So far I enjoy the Sig tremendously.
    Own one 9mm but carry only 40 S&W or 45 ACP. At my age and as little range time as I can carve out I need every advantage I can get. I have been carrying daily for decades in urban, rural and back country of Montana and Washington state. The 10mm allowed me to take a brown bruin in Alaska five years back. Love the caliber.

  4. Mas, your take and mine are similar.

    During my retirement years before I lost my mobility, I considered fishing in the states like Montana, Idaho, Wyoming, etc. I knew I needed bear protection carried on me in a convenient package but didn’t think I could handle a true hand cannon that usually only had 5 rounds. However, I had a Glock 41 that I enjoyed carrying and figured that a Glock 40 would give me the best compromise between power and controllability. Longer barrel for slightly more velocity, large mag capacity, lighter and thinner than a hand cannon and therefore, more likely to be on you while puttering around camp and stream. Getting wet while fishing is also nothing for a Glock. Recoil was also another factor that won me over. As a semi auto the Glock would also reduce the recoil of a 10mm further than a revolver would.

    My over all plan was to place the front sight on the charging bear’s nose and pull the trigger until the bear went down, or until you ran out of ammo and luck. Practice in an indoor range with a paper plate attached to the target holder while a buddy hit the button to advance the target to the shooter was my practice plan.

    Unfortunately, I was never able to make those fishing trips (got too old too fast). If I had, I would have still taken a 12 gauge (20″ barrel and extended mag) with slugs in addition to the the Glock for any occasion where I had access to it in time in camp or on shore. YMMV.

  5. I would opine that the maximum sensible distance for shooting a threat with a handgun is determined by how far away the threat is. The majority of duty and concealed carry handguns are quite capable of the accuracy needed to hit a man sized target at 50 yards or more. Police, military and civilian have used handguns to stop deadly threats at distance for years, some quite recently. A handgun is not the ideal tool but if it’s all you have, it beats rolling over and peeing yourself.

    • I agree. I’m reminded of an instructor who said you only need to shoot 20 yards or so, because further than that you can evade.
      But what if you aren’t protecting just yourself? If a member of my family is in danger at 50 yards, I’d have to do something about it. Hopefully I would have some help, like a pole or column to help steady my aim.
      As I recall the ram IHMSA targets for practical pistol are about as wide as a person, and set at 100 yards or meters.

  6. Being a 1911 fan i just had to have the Delta Elite in SS when it came out. Im sure it was 1986 or 87.
    Mine wasnt up to snuff as the Delta suffered premature barrel link damage and throat erosion. COLT repaied it,
    But sadly i dont have that gun anymore.

  7. I recall reading about the .40 G&A in that magazine in the 1970s. I think the converted a Browning High Power to shoot it.

    • You are correct. Gunsmith John French modified a BHP for Whit Collins’ wildcat .40 G&A. It was discussed in the July 1972 issue of Guns & Ammo magazine. In the previous issue, Collins had outlined the lineage of the .40 caliber handgun cartridges which had led to his development of the .40 G&A.

      The .40 G&A was formed from cut down and reamed .30 Remington cases. In 1977, another Guns & Ammo contributor played with a belted version of the .40 G&A by using cut down and reamed .224 Weatherby Magnum cases. The BHP was the conversion host once again.

  8. I was introduced by the Marines to the 1911 in ‘72. I still carry one today. I have been reloading my 45acp with Enforcer (14g) and 230 XTPs, pushing the round at 1000 fps. I would say a 230 grainer over 1000 FPS is besting most, if not all standard pressure 10MM loads, and that is interesting to me. It does this without getting into +P pressures around 19,000 IIRC. I might just take up handgun hunting.

  9. It is interesting how little technology changes in the field of firearms. In most respects, the technology of the 21st Century has little resemblance to that of the late 19th to early 20th century. For example, we fly in jets or speed around in high-speed automobiles. The old “Horse-and-Buggy” approach is totally obsolete unless you are Amish.

    Yet, in firearms, the 1911 is still going strong and “Ma-Deuce” still soldiers on in many armies. My last handgun purchase, which applies here, was a Dan Wesson Kodiak. This is a long-slide (6-in. barrel) 1911 chambered in 10mm.

    I have a copy of a Winchester catalog (dated April 1900) in front of me. In this catalog, they offer Model 1892 carbines and rifles. The standard barrel length for the rifle is 24 inches. The rifles are offered in various calibers ranging from .25-20 to .44-40. Consider an 1892 rifle chambered in .38-40 (.38 WCF) caliber. From the April 1900 Catalog:

    Model = 1892 Winchester Rifle
    Caliber = .38 WCF
    Bullet Diameter = .401 inch
    Bullet Wt. = 180 Gr. (Pure lead)
    Powder Charge = 38 Gr. FFG Black Powder
    Muzzle Velocity = 1268 FPS (24-inch barrel)
    Penetration = 7 1/2 Dry Pine Boards at 15 feet from muzzle (7/8 inch thick boards)
    Cartridge Capacity = 14 +1 (full length magazine for the 24-inch barrel)

    Tell me, what difference is there between your great-grandfather, armed with an 1892 rifle in .38 WCF, and you armed with a Glock 20 in 10mm today? Sure, you have shrunk the firearm down from a light rifle to a handgun. The handgun is semi-auto so it might be a bit faster to fire than the lever-action rifle although a ’92 is very slick and fast to fire in the hands of someone who knows how to work it. On the positive side, the rifle offers a longer sight radius plus three points of contact for a steadier hold and more accurate aim. The ballistics are almost identical.

    Your bullet might be a bit more “high-tech” today versus the old “pure lead” slug. Still, will a bear or a pig really notice the difference?

    If I had to face a bear today, I might well select the old Model 1892 in .38 WCF over a modern Glock 20. I am sure that I could score better hits with it over the pistol.

    I sometimes think that the firearms market is driven more by current fads then by any practical concerns. For a while, the .40 S&W was the “hot” round to have. A darling of law-enforcement. Nowadays, it is “out-of-fashion” and we are back into another “Wonder-Nine” phase.

    What will the new fad be tomorrow? Wise old Great-Grandpa will just shrug and walk into the woods with his trusty old ’92 or ’94 (in thirty-thirty) in his hand! 🙂

  10. If I could only have one handgun, it would be a Glock 20 10mm. I became an ardent proponent of both the gun & the caliber when I bought one of the first ones made available to the public after realizing the potential of that combination. At the time, the .357 Magnum 125 gr. JHP was considered to be the best self-defense/law enforcement caliber available at 1450 fps. out of a 4″ barrel & it’s still a great choice. But Cor-Bon makes a 10mm 135 gr. JHP at 1450 fps. out of a 4″ barrel, making it possible to shoot an even more powerful load out of a Glock semi-auto with a 15+1 round capacity!!! Furthermore, the Glock 20 has less felt recoil than other 10mm pistols due to a heavier slide, a lower bore axis, & a wider grip than those other handguns do, making it easy to rapid fire. In addition, Glocks are the most reliable semi-autos that I know of & they are readily available for well under $600. The only drawback to a Glock 20 is that it has a long grip, which could be troublesome for those with small hands. However, the Glock 20 SF (short frame) solves that problem. Even though my hands are large enough to shoot with the long grip, I do prefer the short frame version.

    I’m thankful that 10mm is making a comeback because now there is a much wider variety of ammunition & bullet weights to choose from. Even so, it wouldn’t be my first choice for protection against large brown bears, although it reportedly has been effective with heavy bear loads. It would be great for black bears & other similar sized predators, though. It is, however, my first choice for a SHTF handgun when you KNOW there’s going to be trouble.

    • Ruger makes a GP100 revolver in 10mm as an alternative to .357 and semi-auto. A mega-shot semiauto 10mm that is big in combative self-defense, and a possibly more reliably operating weapon in a revolver in the same caliber, hopefully give you two handguns that can shoot the same 230-grain bullet, for example, an issue pertinent to “predator control” over the usual 180-grain maximum bullet weight in .357s. A revolver is surely more of a secure one-hand operation overall than a semiauto, something to remember when you are way out in the timber and run the risk of a hand injury of one kind or another. If you carry a powerful long gun like a 12 gauge shotgun or a heavy caliber rifle, as I often have, that may be all you need to survive, and a handgun in addition may be too much of an extra burden. If you choose to rely solely on handgun, however, which is definitely not all bad depending on conditions, I would more strictly observe the principle that 2 are one, and 1 is none. Negative consequences regarding predators, and even moose, do make very high stakes.

  11. Ah, memories. My issue 10 mm is down in the safe, I expect my grand kids will get $$$$$ for it someday along with the spare magazines, factory letter and a personal note. And a few spare parts.

    I’m not that far from Quantico and had a number of friends in the FBI. Mas’s version of the 10 mm adoption is ah, sanitized. I had copies of some internal memos, including one after adoption that advised agents that whatever the side arm question, the 10 mm was the answer. We’ll let it go at that. HK even made an MP5 variant for it. Allegedly a massive improvement over the 9 from extended effective range.

    The FBI adopted it, the VSP adopted it and since our higher ups were ex VSPs we adopted it. The .40 came out before we made the purchase and I formally requested we pause as I predicted what came next. We bought anyway. Our folks managed to shoot the 1006 very well, even given it’s size. Falling plates at 100 yards not a problem from prone, put about 1/2 the front sight dot above the rear sight and press the trigger. We dropped it-for the M&P40- after we couldn’t get ammo in the needed quantities.

    More power than really necessary for duty/personal protection (from 2 legged predators) it does have some use in the field. Be nice to see a locked breech PCC in 10 mm. At a reasonable price.

  12. When I’m in the woods to invite Bambi home for dinner, my chest rig holds an ancient pawn shop GLOCK 21 with a Storm Lake 10mm conversion barrel (conventional rifling and full chamber support) and a stout Wolff recoil spring. It’s full of Buffalo Bore’s spiciest: 220gr hard cast with 1200fps of urgency along its way.

    It’s the wrong tool for the job if the problem you’re trying to solve involves two-legged city predators. But for furry fangy unfriendly four-footed fauna, it’s just the ticket.

  13. Recoil is the main reason I do not own a 10mm. I hunted with the 44 Mag in Ruger Super Blackhawk, Thompson Contender and S&W Model 29 for forty years and killed a lot of game with them. It’s still my favorite cartridge, but I’m 77 years now and pretty stove up with arthritis and the heavy recoil of the 44 hurts long after I’m done shooting. Because of that alone I have downgraded to 9mm. My personal CC is the Springfield Hellcat with 14 rounds. My home defense weapons are Glock 17 and 19 and Remington 12 gauge Home Defense. I can still hit a 12” steel plate at 25 yards with damn few misses with the 9mm. I doubt I could do that anymore with the 44 mag. Past 25 yards it’s my trusty AR and 30 round mag.

  14. Here in NW Wyoming I’m liable to run into a wide variety of critters while fishing some of the streams and rivers. In order of (mostly) probability for the dangerous ones they include coyote, cougar, black bear and grizzly bear. My carry gun is typically a Sig C3 (officer’s size frame with a commander length barrel/slide) in .45 ACP. Carry ammo is 230 grain JHP. Seven rounds (plus one) in the pistol and seven more in a mag carrier on my side.

    In my estimation this is sufficient for any two-legged predator both in town or out, and probably effective on the first three of the four critters mentioned. But in my estimation any pistol or revolver is a last-ditch, OMF’nG resource to use against a grizzly. A 12-ga with slug is about the most portable thing that would still have enough umph to slow down a grizzly, and my personal choice would be something like a 7mm mag from 300 yards away, far enough it wouldn’t even know I was there…which isn’t the point. We’re talking about something I can easily carry while fishing. For close-up grizzly bear defense pepper spray is useless (see the humorous sign about bear scat), and a pistol/revolver only slightly less so.

    My personal problem is that I simply can’t handle the recoil and report from a .44 magnum firing full-house rounds. .44 Spl is okay, but after one cylinder of magnums even from a heavy 6″ barreled Ruger and I start to develop a flinch. A 10mm may offer a (slight) step up from a .45, but I can’t stand shooting a Glock (I had a 30S a while back…the trigger from heck compared to a 1911). And caliber proliferation is something I’m just not going to do.

    So I’ll stick with what I’ve been shooting for over 50 years, and carrying for over 20 years, and hope that if worse comes to worst that a half-dozen rounds of .45 will be enough to solve a bear problem.

    • Esteemed Blackwing 1, I knew a Canadian miner who packed a .45 ACP in the bush, probably shot several bear, and always said the .45 “is not too bad.” IMHO, though, you would be better off alternating ball ammo between hollow points to give you more of a chance per magazine of penetrating a bear skull, which will likely be your shot of choice, if given one, and at close range. You may be skating on ice with the short barrel and hollow points, and much more effective 1911-style handguns are available, such as a Ruger 10mm vetted by a gunsmith, but what you have may be better than nothing. May God bless you and keep you. It is hard to beat woods loafing for relaxation.

    • Buffalo Bore ammo is available in most calibers. This even includes some old ones like .32 S&W Long and .38 S&W (the old round, not .38 Special).

      See this link for a listing of the calibers that they offer for handguns (they also sell rifle ammo):

      With respect to the comment by Blackwing1 (above), Buffalo Bore sells a .45 ACP +P Outdoorsman load using a heavy 255 hard cast bullet. This should out-penetrate even hardball in your commander size pistol. You might try a box in your SIG. If it shoots good, you might carry this ammo in bear country. It would give you a penetration edge over your 230 JHP round.

      With this +P round, you might want to increase the strength of your recoil spring. You could go to Wolff Gun Springs and pick up an extra strength recoil spring for your pistol. I would guess that a 20 or 22 lbs. spring would work. You are probably running an 18 lb. recoil spring in your SIG currently?

  15. Strategic Steve: Thank you for the kind thoughts. I’m not too worried about the difference between a ball or JHP round, and I’m far more likely to run into a situation where I don’t need or even want the penetration (like in our small town, should [avert] something happen). I carry everywhere it’s legal, which around here excludes only the courthouse and police station/jail, and I carry all the time. I’m far more likely to run into two-legged predators than 4-legged these days.

    TN MAN: Thank you also for the suggestion, but I’m not going to adapt the Sig to be a “bear gun” since it’s my every-day carry (it’s got an aluminum frame, and I got sore from toting around a Springfield SST 1911A1).

    Quite honestly the only times I’ve seen a grizzly OUTSIDE of the Park (Yellowstone, that is) have been in areas like Sunlight Basin, where they’ve been conveniently located on the far side of a valley, just about right to watch with my 15x binoculars as they make their way into the woods. I don’t fish in the Park, and certainly don’t hike back-country in there…all the griz I’ve seen there have been from the comfort of the cab of the truck. I’m far likelier to shoot a bear with a camera, and I’m hoping it stays that way.


Please enter your comment!
Please enter your name here