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In my last State Your Case article, I talked about the 9mm vs. .40 S&W. The .40 got a raw deal in that discussion, but I did my best to defend it and make it as equal of a comparison as possible. Today we’re looking at two other titans of the automatic pistol world: the 10mm Auto and .45 ACP. These two rounds occupy the upper portion of the autopistol market and often vie for popularity in the field, but rarely on the competition line.

The .45 ACP has been around for well over a century. Very few cartridges make it that long and this old soldier has seen it all. In fact, it is still in active military service today in platforms little different from those of the First World War. The .45 ACP is a round that is deeply engrained in American culture and is often considered to be one of the greatest handgun rounds ever made.

Greatness is a matter of perspective, as many consider the round to be underpowered and inadequate in terms of capacity and utility. Some today even say that it is completely inferior to the 10mm Auto, which is often compared to the .357 Magnum. These points against the .45 ACP are valid, but the 10mm Auto is far from perfect and has had a much, much spottier past than the .45 ACP.

The old standard for .45 ACP is a 230gr bullet at 850fps. 10mm fans love to use this as a point of comparison, as the pre-FBI 10mm loads were hot, launching 200gr bullets about 1,200fps, which was a significant gain over the old .45. What 10mm fans hate to talk about is the neutering and subsequent abandonment of their favorite cartridge and the improvements across the board in ammunition technology that have seen the .45 ACP make up lost ground against smaller, more popular rounds like 9mm.

Unlike the .45 ACP, the 10mm gained a reputation as a wrist-wrencher, with the FBI, after testing and briefly adopting it, rejecting the wonder cartridge for the less powerful ‘10mm Lite’ variant, which was loaded at about 1,050fps. This round was later reduced in length and became the .40 S&W. For a great many years, the 10mm was loaded light, and it eventually lost relevance because the .40 S&W did everything it did, but could fit in a smaller gun.

The .40 S&W/FBI scandal nearly ended the 10mm’s run on the commercial market and it would have likely died right then and there if not for a TV show. The only well-known film character to carry a 10mm Auto was Sonny Crockett on Miami Vice. Just like today’s The Walking Dead-motivated Colt Python craze, Sonny’s Bren Ten caused a spike in the price of the iffy-quality pistol and did more to save the reputation of the 10mm than any gun marketing company ever could’ve managed.

Unlike the 10mm, the .45 ACP has never struggled in pop culture representation. The big .45 is usually the gun of the hero, and is more often than not a 1911. This combination of gun and ammo is usually in the hands of the aged veteran like Clint Eastwood in Gran Torino, where it shows grit and determination, but it also had a starring role in Keanu Reeve’s recent action extravaganza John Wick 2, where an entire scene was devoted to the .45 and the 1911. The .45 caliber pistol, be it an old Colt or a modern 1911, is an integral part of the American soul.

On the technical side of things, the 10mm Auto beats the .45 ACP in just about every way. In two nearly identical guns, such as the GLOCK 20 and GLOCK 21, the 10mm has greater capacity, higher velocity, flatter trajectory, and weighs basically the same loaded as the .45 version, if not less. These same things carry over to virtually every platform that is available in these chamberings.

In terms of ammunition, the 10mm easily runs circles around the .45 ACP. Not only is it more powerful, but it also has bullets with much higher sectional density that are able to penetrate better than most magnum revolver rounds less than .41 Magnum. This makes the 10mm a great choice for the woods and many large bears have been put down by it.

By comparison, the .45 ACP has a large bullet, but it is fairly stout and isn’t great at deep penetration on game animals. Pistol hunting has become very popular in the last few years and the 10mm has benefitted over the .45 ACP because of this. Pistol hunting happens at bow hunting distances in most cases, and the 10mm simply delivers better performance on animals given identical platforms and range.

Where the 10mm suffers compared to the .45 ACP is on the competition line. Many types of competition specify the .45 ACP, but don’t necessarily ban the 10mm. The reason the 10mm isn’t popular in matches is because it isn’t a very friendly round in volume. Granted, there will be the He-Man out there that laughs it off, but the 10mm in its full-power form produces far greater recoil than a .45 ACP does, which slows follow-up shots and can reduce scores over time. Reduced power loads can be used, but then again, that’s why the .40 S&W exists. If you shoot a lot, the .45 is a cheaper and more plentiful option that will do well across the board.

So what do I pick as the winner here? It may seem odd, but I have to go with .45 ACP. Yes, I can see the comments in my head right now. “B…but Josh, you’re a know-nothing hipster who doesn’t get guns and tactical response…and foot pounds… and… retained energy…” Well, the thing is, I do understand all of that, and I still picked the .45 ACP as the winner here and I’m happy to explain.

The .45 ACP is an American staple. All the things that make it lag behind 10mm Auto also make it lag behind .357 Mag, .44 Mag, .460 S&W, and many others when power is the only thing considered and behind 9mm when capacity is the only thing looked at. The .45 is commonly carried and is well understood by the general public, which regards it as a magical manstopper. Thing is, they aren’t wrong for thinking that way because it is, for the most part, true. If the 10mm was all that and a bag of chips, it would never have been cut down to .40 S&W in the first place. Superior ballistics pale in comparison to tradition, and there is hardly a bore more significant to the American tradition than .45.

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    • Oh, come on John. If the .40 got a raw deal than of course the limp .45 will get the shaft in this go-round. Everyone knows the 10mm is superior in every way possible except historical significance and depth of fanboydom.


    • The previous comparison should have been .40 S&W vs. 10MM (not against 9MM). Both bigger rounds are very close to the same diameter. Both are stupid over-pressure, unnecessarily expensive, non-NATO rounds that only exist for ignorant rednecks who don’t understand that 9MM is entirely enough for a pistol round. You should saved .45ACP for the “which is more obsolete, .25 auto vs .32ACP vs .45ACP” question. No, John Browning was NOT a genius [certainly] when it comes to designing pistol cartridges, or firearms that are easy to service. I’ll admit that John Browning was rather adept at designing unnecessarily heavy “boat anchor” guns for our military to schlep around all over Europe…poor guys.

      • .40S&W and 10mm bullets are the exact same diameter. In many cases, it is the same bullet that is loaded, especially FMJ.

        • I did. Dropped where he stood. 124 Grain Federal Hydra Shok. One shot to the upper chest as he faced quartering toward me. Penetrated both lungs, his heart, and 19 inches deep. 35 yards and dead before I got to him.

      • John Browning was a genius. He did what he did without standing on the shoulders of better men, like later inventors did to him. He was limited to the powders of the time, the materials of the time and he had to change the military minds of the time.

      • Wait, if I have both 9mm AND 10mm, would I be a semi-enlightened redneck, or just mostly ignorant?

        If it bumped my score to semi-enlightened how may penalty points would I get for .458 Socom and 6.5 Grendel?

        • Madcapp likes to rant about things of which he has very little knowledge. Which includes most of things unfortunately.

      • @Madcapp: You are an incredibly uneducated and ill-informed individual, my friend. For starters, the 10mm in a full power loading is rated at lower pressures than 9mm +P per SAAMI specification guidelines (37,500 PSI vs 38,500 PSI) and only marginally higher than a 9mm at standard pressure (35,000 PSI), so perhaps before you open up your mouth again you may want to educate yourself on the facts first so you don’t sound like such a buffoon. Secondly, while the 9mm is sufficient with modern ammunition technology in most self-defense encounters, it’s barrier penetration performance leaves much to be desired and it has little value for anything other than two-legged prey.

        The 10mm on the other hand, excels at barrier penetration and has a much broader operating range that allows it to be loaded light enough for self-defense applications that still fall within the FBI guidelines of 12-18 inches of penetration in ballistic gelatin or loaded at full-power specification for hunting of medium-large game and is an exemplary caliber for woods defense. Thus, caling other people “rednecks” for appreciating the virtues of the 10mm and then basing your argument on the fact that 9mm is sufficient for most self-defense applications makes about as much sense as saying that V8 engines have no place in the automotive world because most cars could get by with a 4-cylinder.

        It’s an asinine argument that only a person completely devoid of common sense and who barely passes the legal threshold for being mentally retarded would make, so I don’t think you’re in a position to be judging anyone, champ. Now why don’t you do us all a favor and go back to the kids table where you belong so the adults can talk?👌

    • Why even bother with the weak 10mm when there’s .460 Rowland. All the power of a real (that means not girly) magnum, in an auto cartridge about the same size as a .45.

  1. Rural fokelores…Deep Woods Cryptids…Bigfoot and Nephilim Giants…See rural legends: Giant of Kandahar… Giants of Lovelock cave…Dogman…The Rake…Hell ! .50 ae or .500 s&w or above! LOL!

  2. .45acp is the more versatile round in my opinion. There are loads that match the old black powder 255gr hardcast at 1,000 FPS, and that round was known to be a penetrator. Not to mention that there is .45Acp+p and .45 super(with a few mods to most guns). Plus the added bonus of .45 being a whole lot more common.

    45acp is a lower pressure round so your gun will take less of a beating, the brass will last a very long time, and if you’re shooting indoors the muzzle blast doesn’t make everyone else on the line flinch (if you are about that sort of thing).

    And the HK USP only goes up to .45acp. If that gun had a factory chambering for 10mm I’d probably jump on the 10mm bandwagon too.

  3. The only times I’d choose a 45ACP over a 10mm is if I’m buying a 1911 or trying to shoot subsonic ammo. Even then I’d still like to get another 1911 in 10mm. I love the Colt Delta Elite.

  4. The 10mm was “cut down” because the “FBI Load” was down-loaded from the full potential of the 10mm for the FBI’s smaller agents with smaller hands who could not control a 10mm pistol with the full-house loads. Most any 10mm handgun with a double-stack magazine is quite the handful, and you’d better have large mitts to get your fingers wrapped well around it.

    The result was that the 10mm case with the FBI load had lots of unused space, and S&W suggested “Hey, let’s cut down the 10’s case, keep the load/bullet/primer, and we can keep the double-stack, but reduce the size of the grip…”

    And lo! The .40 Short & Wimpy was born. S&W marketing could have called it the “10mm Short” and been a tad more honest in their marketing.

    Now, the .45 ACP….

    The important thing here for the .45 ACP is that, like the .45 Colt (aka .45 “Long Colt”), the cartridge is capable of so much more in a modern firearm than it is in its original design firearms. The problem in both cartridges’ situations is the insufficient support for the case in the chamber, so they were never designed for high pressure loads. The brass wasn’t designed for high pressure, the guns into which it was chambered (the 1911, M3 Grease Gun, Thompson sub-gun, etc) were not designed for high pressure rounds.

    Going back to “before the 1911,” in the .45 Colt, Colt SAA chambers were cut on the large side, so as to allow easy extraction in the face of the sort of soot & powder residue from actual black powder. Higher pressure loads tended to split the case, from the mouth moving backwards. The pre-Nitro proofed SAA’s could not withstand the pressure of nitrocellulose powders, and that was due to metallurgy of the SAA itself (I won’t get off into the weeds on pre-“VP” proofed SAA’s and what they were made of – it’s fascinating for some people, but most people here would likely just go “huh, so what’s that mean?”)

    Since there are so many non-nitro proofed revolvers out there, the .45 Colt remains down-loaded to very, very modest pressure levels – eg, 14,000 psi. SAAMI likes to call out that pressure limit as “maximum average pressure,” or “MAP.”

    The .45 ACP is a little better, having been designed in the era when nitro powders were not becoming dominant. The .45 ACP has a SAAMI MAP of 21,000 PSI.

    Fast-forward about 60 years of semi-auto pistol development, and much more development in the area of smokeless nitrocellulose powders: The 10mm Auto has a MAP of 37,500 PSI. That’s not that remarkable, BTW… the 9×19 is up around 35,000 PSI.

    Now, if you have a .45 Auto with a fully supported chamber (eg, a ramped barrel in a 1911, or a modern pistol with a fully supported chamber barrel), you can load the .45 ACP hotter than SAAMI spec. .45 ACP +P is about 23K PS, and that’s still conservative – so as to allow the odd +P round to not grenade a normal 1911. Some people running ramped barrels are running hotter loads than +P. In some cases, you can get a barrel that allows even hotter loads with heavier-walled brass, eg, the .45 Super. With a 1911 sporting a 5″ barrel that is designed for the .45 Super, you can see velocities for a 185gr bullet over 1300 fps. That’s the equal of the 10mm loaded to potential.

    Same deal for a .45 Colt – if you have a modern firearm (eg, Ruger or similar stout revolver), with a minimum-sized chamber for a .45 Colt, you can run the pressure up into the mid-high 20K PSI area and see substantial improvements in velocities. John Linebaugh modifies Ruger revolvers to allow them to push the .45 Colt to amazing performance levels – hurling 250+ grain pills downrange at over 1,000 fps.

    The obvious problem is that either of these historic-but-now-hot rounds could be chambered in a firearm with insufficient metallurgy, or a non-supported chamber, etc – and at these high pressure levels, you will have a very high likelihood of a case failure, perhaps also a barrel/chamber failure, and you’ll have a really bad day.

    BTW, this was the problem withe the S&W .38/44 (a forerunner to the .357 Magnum) – you could drop .38/44 rounds into the average M&P/Model 10, and it was kaboom time. This is why the .357 case had the added length – it prevented anyone from chambering a .357 round in a bog-standard .38 chamber. Same deal with the .44 Mag vs. .44 Special, etc. Elmer Keith blew up more than a couple of SAA’s and other revolvers shovelling heaps of powder into a .44 Special case during his experiments leading to the .44 Magnum.

    The 10mm is a higher pressure round because it benefits from a century of handgun design refinement, a half-century of development of semi-auto handguns, and prior high pressure cartridges (.357, .44 Mag, .38 Super) that showed what was needed to make a handgun survive the issues the high pressure the 10mm would bring to bear on the handgun. The 10mm had some teething problems in some guns – frame cracking, etc.

    All this theory comes down to this: You can load these old cartridges ferociously hot with modern powders. These cases were developed for black powder (.45 Colt) and “fluffy” nitro powders (.45 ACP) that mostly filled the cases. With today’s hot pistol/shotgun powders, you could triple or double+ charge these cases, with the sort of results you’d expect from such overloads.

    If you’re reloading these century+ old cartridges, you must pay attention to what you’re doing at all times. The face you save may be your own.

    Now, which do I prefer of the .45 ACP or 10mm? I like both, that’s why I own pistols in both (both 1911’s, and one G36). The .45 ACP would be my preference if I had to light it off without hearing protection.

    • Right on the money here; the question of pressure is the big one. .45 ACP is certainly a “lazy” cartridge in terms of pressure. Not only that but also as said we have to view .45 ACP through the window of the time it was made and the resources available which are nowhere near as good as now. Modern guns and powders really help things along when coupled with a few light mods and some .45 Super brass.

      The amount powder volume has gone down in ~125 years is insane, look at a charge of Bullseye that’d get you a standard velocity .38 Special round vs filling the entire case with black powder to the bullet level which was the guide line used at the time.

    • Fully agree. I’d add that anyone who intends to regularly shoot .45 Super or hot .45ACP loads should use appropriate-strength springs.

  5. versatile sub or supersonic.
    Good round for a silencer.
    Available anywhere.

    Upgrades easily to super, +p as there’s lots of room on the max psi.

    Nice push vs the painful kick of a 10mm

    Journalists discuss the .10 mm reducing its cross sectional area by 10,000; never happens on the mighty forty-five…

    Taylor Knock Out factor on a 45 super hard cast is up there with the ten.

    Works in the Governor or the Glock.

  6. Kudos to the author for claiming the 10mm is often compared to the .357 ma gnum instead of the .41 magn um. Which on it’s face would be true, kind of like Thedonald Trump is often compared to Hitler though.

    • Doh! Should have read through the whole article before commenting.

      ‘Not only is it more powerful, but it also has bu llets with much higher sectional density that are able to penetrate better than most ma gnum rev olver rou nds less than .41 Magn um.’

      For the record, a 158gr. .357 slug has about the same sectional density as a 200gr. 10mm. There’s no way the 10 can come close the .357 when it comes to penetration.

      • Shhhhhhhhhhhhh!!! Don’t bring up that great 10mm is more like good .357 than 44 Magnum, the keyboarded commandos will find us! I was cyber assaulted on YouTube for making such a point. Also don’t try to explain to people what would actually happen if they had to fire a Glock 29 using their off hand in a sticky situation, they will insist that limp wristing a 10mm loaded with buffalo bore 200 grain hardcast ammo while stressed out and bleeding is an impossiblity, and you will be downvoted off the page for making such a rational observation.

        • Indeed. 10mm often sickeningly gets compared to .44 mag online by tons of people who have probably never even shot either round. There is no comparison between the two. Comparing .44 and 10mm is like comparing a .338 and 7.62 soviet.

  7. This is a discussion for rookies. There is no “vs.” It’s like asking “blue vs red.” Meaningless clickbait.

  8. My opinion, the .45 acp is obsolete. It brings nothing to the table anymore.
    10mm is a powerful niche cartridge.
    I own both, carry a.40, recently bought a 9X19 and lust for the.38 Super.
    Shoot them all, use the right tool for every job. Have a big tool box.

    • I had been thinking of putting a 1911 Commander together in .38 Super. Then I found out about the 9×23 Winchester.

      If you’re going to go for a high-pressure, blazing fast round, then do it up correctly. The 9×2323 Winchester, with brass made by Winchester (which has a thicker case wall) is the way to go.

      • DG is correct. The Starline brass is prone to bulging in a chamber which is not fully supported. The SAAMI MAP for 9×23 Winchester is 55,000 psi. 😳 Dane Burns was a strong 9×23 Winchester advocate.

        DG, in your build, are you planning on using a fully-supported chamber? A compensator? Do you have concerns about COAL with respect to reliable feeding from the magazine?

        • I won’t put a comp on any carry pistol I have. I think they’re a horrible feature on a carry gun – it’s a place for dust, lint, crap, etc to get into the barrel.

          Fully-supported chamber? Of course. There’s no point in doing a .38 Super, 9×21 or 9×23 and leaving the pressure potential on the table.

          The COAL issue. I’m not sure yet how I plan to address that. When I get the pistol together here in the next year, I might write up how I addressed that. I think a 9×23 in a Commander-sized pistol would be the ultimate CCW rig, albeit a damn noisy one. I could get all the potential of a .357, the magazine capacity of a 9×19, and the trigger pull of a 1911.

    • Mike Oregon,

      If you were constrained to ball ammunition for some reason, then the .45 ACP would be the premier semi-auto man-stopper platform.

      And why would someone be constrained to ball ammunition? Cost. Premium ammunition with hollowpoint bullets (in pretty much any handgun caliber) cost about $1 per round. If you wanted to have 1000 rounds on hand for a societal meltdown, that would cost about $1000 which could easily be beyond reach of many people. On the other hand, 1000 rounds of .45 ACP ball ammunition would cost something like $330. That is within reach of most people.

  9. Why choose? Get a Glock 21 with a 10mm conversion barrel so you can shoot both.

    A lot of other 45 platforms (including 1911s) can also readily be converted to 10mm with a simple barrel and mag swap.

  10. Load the 45 (read 45 Super or 460 Rowland) to the same/near same pressure as the 10 and 45 remains on top all the way. With the 45 Super, you can have a regular 45 – 45+P and a 45 Super in the same make/model pistol. THAT friends is versatility with PLENTY of cases/bullets available. GOTTA’ LOVE IT!!!

  11. I have a 1911 in 10mm. The weight settles down the recoil nicely, even with full power Underwood loads. It’s a lot of fun to shoot.

    • Now that’s the best of both worlds right there: heavy steel frame to absorb recoil, and a single-stack mag to keep the grip manageable.

  12. My only input on caliber wars is to buy guns in both. I can’t imagine a scenario where someone says “Gee, I wish I didn’t have so many guns”. Especially with the coming unpleasantness.

    • I knew a guy who referred to his occasional (every 10 years or so) “caliber reduction sales”, cutting down the number of firearms with near-identical performance he had to buy different ammo for. Made sense to me.

  13. You completely missed the critically important criteria of “Can the round Destroy Souls On Impact”?

    .45 dominates this area completely.

  14. I have a Commander size 1911 in 10mm and a Officers in 45.
    My preference and both are equal in shootability (not a word I know) is the 10mm with full power loads. Equally controllable equally shootable. Not much difference in weight as an EDC.
    I believe in carrying the biggest load one can and shoot well.

  15. the .45 was designed to stop men, not bears or blue whales.

    • i remembered that as well; but I don’t recall whether he ever actually shot anyone with it. Miami Vice featured a lot more gunfights.

  16. The biggest thing that keeps me picking .45 over 10mm is that almost all of the locally available ammo is watered down enough that it’s not worth the extra cost. If it didn’t double as the world’s softest shooting. 40 my poor G20 would probably never make it out of the safe.

    • Until Sig 10mm ball went on the market 10mm was twice the price. Now it is within a couple of dollars. It makes 10mm more attractive.

  17. One day I bought 1,500 rounds of 45 ACP and this had the clerks talking “you just bought 50% more than we sell of 10mm in a quarter.”

    I’ve yet to see anyone firing 10mm at the range in the last 150+ times I’ve been to the range. Every time I see 9mm, 45 ACP, 22LR, and.223/5.56 and half the time 12 gauge or an AK-47. I’ve seen .460/.454 Casull, 45-70, 7.92mm Mauser, 30-06, .303, 30-30, 308, 5.7mm, 357 SIG, 357 mag, 38 spl, 44 mag, 20 gauge, 410 gauge, .41 mag, 22 mag, Creedmore, Grendel, Beowulk, blackout, and pretty much every mass produced Russian caliber.

    But not 10mm.

    • In my range you are only allowed to approach the parking lot under a mile if you are going to shoot creedmoor or 10mm. We operate so we don’t want any noobs and their BB guns!

  18. Screw Miami Vice. I only bought my Glock 20 because Agent Franks from Monster Hunter International carries a pair of G20s loaded with hollow.

    And league shooters use .45 ACP downloaded to 500 fps. They call them powder puffs.

  19. If you put the 10mm and the 45acp in high point carbines you get way more power out of both.These carbines are small and easy to carry in your vehicle for a lot more knock down power if you need it.I have seen a longer carbine barrel increase bullet speed by 200 ft. Per second and ft. Lbs. by 50 or more.

    • Or you could keep a Henry Big Boy in you car instead. Same capacity, better “knockdown power,” and WAY f*cking cooler. And they only cost twice as much and reload less than half as quickly, but… WAY f*cking cooler!!!

  20. Haha that good ole clickbait of the caliber war. Good job TTAG. Yes, you got me too, obviously.

      • .22 short every day of the week (and twice on Sundays), because screw hearing protection. Who needs a silencer when you have .22 short?

        • I am afraid I have some very bad news for you. Hearing experts determined decades ago the worst caliber to use as far as hearing destruction is concerned is the .22 rim fire. Now how could this ever be, it makes no sense you might say. Very wrong as the decibels are just under the range that lets the noise travel up into the inner ear which creates the most damage. Very loud noises actually and partially shut off noise traveling up the ear canal. Now this does not mean loud noises also not will destroy your hearing, it means the .22 will do it much, much faster.

    • In before some keyboard commando says: Well a hot loaded .22 with the right bullet is basically a .50 BMG anyway so…

    • The FL Highway Patrol still issues Glock in 45gap. I will never understand why they made this choice to begin with, they took the bait.

  21. Josh, your “history” is BS. 10mm was advocated by Col. Jeff Cooper, and he set the performance specs. Norma made the round, and Bren made the pistol in 1983, based on the CZ-75. Miama Vicrle premiered in 1984, and it did generate excitement for the Bren Ten, Steyr Aug, and other cool stuff, like pink and teal shirt, 5 o’clock shadow, and linen suits. Bren had production problems, and owners would go insane seeing Crockett destroying magazines that their guns didn’t come with and they couldn’t buy. The 10mm pretty much died because of Bren’s incompetence, despite it’s desirability. Then in 1986, the Miami Shootout happened, and the FBI got serious about an evidence-based cartridge selection. Colt came out with the Delta Elite (10mm 1911) in 1987, which made it generally available to the public. After running tests, the 10mm was adopted in 1989, which is when Miami Vice was going off the air.

    • Dornaus & Dixon made the Bren Ten. The name “Bren” with respect to the British magazine-fed LMG of the 1930’s was a combination of Brno and Enfield.

      I agree with you in that Dornaus & Dixon were terrible to their customers. For example, as you pointed out, magazines were very difficult to find, very expensive, and often did not come with the pistol.

  22. 10mm for hunting with a semi auto (.357 mag is better but that won’t fit in a semi auto gun.) 45 for the range and combat.

  23. The 10mm has been pretty much of a flop since its inception by the influence of Jeff Cooper who seemed to get everything wrong about the peoples self defense preferences as well as his idiotic scout rifle fantasy which also went over like a lead balloon. Despite Coopers rantings on how bad the 9×19 was much to his embarrassment the 9mm only got even more popular as he was ranting and screaming from the roof tops against it and his new baby the 10mm only became a bigger and bigger flop.

    Coopers new baby was the ill conceived 10mm which he claimed was the answer to something better than the .45 acp (the only time he ever hinted the .45acp was not the best defense caliber) The FBI abandoned the 10mm after brief;y issuing it with disastrous results. The weapons issued did not hold up to its pounding recoil and the people shooting it did not do their best shooting with it either and its magazine capacity was less as well. It was a hated round. In the world of hunting with a pistol which is more of an idiotic stunt as compared to using a rifle or shotgun the 10mm still takes a back seat to more powerful revolver rounds which have gotten bigger and bigger and way more powerful over time which left the 10mm with no real purpose any more in the shooting world.

    The .45acp has always been a failure of cartridge with very poor penetration, a looping trajectory, and low magazine capacity in most pistols chambered for it and too heavy a recoil for the average Joe who does not shoot it as well with full power loads as compared to the full power loads of the universally popular 9×19. The .45 comes in a bigger and heavier size gun and has a larger grip circumference not suited to many smaller peoples hands and which is not as concealable or as comfortable to carry than the smaller and lighter size 9×19 which is yet another reason for the 9×19’s vast popularity with both the police and the shooting public. The worlds armies and police departments have mostly rejected the .45 acp since it was first invented. Even John Browning never wanted it as his original series of pre-1911 guns were chambered for a .38 caliber cartridge and he was forced to change the guns caliber by the military who believed bigger was better. History proved old John correct in his original marketing idea of a .38 size round rather than a bigger caliber one as worlds police and military and civilian sales for over 100 years have proven which caliber all these groups wanted and bought and still buy and that was a .38/9mm size caliber. And contrary to heroic G.I. Joe tales of WWII with the 1911 many U.S. service men preferred the 9mm over the .45acp and proved it by using many captured 9mm pistols especially the holy grail of all WWII 9mm pistols the FN high capacity High Power Pistol which German, Japanese, Chinese and U.S. Personal went to great lengths to get a hold off. One Japanese Air Force General was even induced to stay behind in China after WWII was over to train the Chinese Air Force by being offered a Canadian High Power Pistol which was the only inducement that changed his mind after he stated he was going home.

    When you really think about it the difference in diameter of the 10mm and the .45 acp is only 5 , 100ths of an inch and the difference in diameter of the .45 acp and the 9mm is only 1/10 of an inch but the mesmerized followers of the guru and high priest of the 1911 people Jeff Cooper insinuated that this 1/10 of an inch difference would blow a man off his feet clear into the next county and was only slightly less lethal than a bolt of lighting out of the blue while the 9mm was only just powerful enough to kill a butterfly that had been sick with the flu for a week. Of course the worlds militaries have been using it since 1908 so maybe they were hypnotized by it for all these decades and all the dead combat personnel really never were harmed by it at all.

    I personally do not need nor want either the 10mm or the .45acp although those that believe in the fairy tails of killing power with bigger calibers or for that matter any caliber pistol have the right to blow their money on any fantasy that turns their crank. The gun industry is only too happy to market it if your dumb enough to buy it. And if you think I am being facetious look how many people today still salivate over owning one of the worst combat shotguns ever made, the Street Sweeper and later banned by the A.T.F who were dumber than the people who bought them. Snazzy and sensational names like the “Street Sweeper: or “Black Talon” sell ammo or guns and scare the shit out of the A.T.F and as P.T. Barnum once said “There is a sucker born every minute”. He should have added “Especially with the gun and ammo buying public. Everyone seems to want “the latest and the greatest” which in the end usually proves to be not so great after all.

  24. My vote is 9 mm for defense against humans, and 10 mm against bears. With bears, and esp brown bears, you need penetration, and 10 mm penetrates a lot better than .45, because it is thinner and much faster. In MT, as you get closer to Glacier (and probably Yellowstone), the sales of 10 mm jumps significantly.

  25. what ever the caliber, you need to practice with it. that cost’s money, 10mm guns and ammo are more expensive than .45acp. It’s real awesome you have cannon in your holster but can you afford to practice and shoot it well in anything other than a range situation? So by this reasoning, I’m more afraid of the person that practices shooting 10,000 rounds of 22lr, than the one that shoots 100 of 10mm.
    …which is why I vote .45 acp. it an opinion, deal with it. find your own facts.

  26. I choose the .45 ACP for the following reasons:
    1. Ammo is cheaper
    2. My old beat up arthritic wrists don’t like heavy recoil
    3. My local shops carry lots of .45, but little if any 10MM
    4. I had my .45 before the 10MM came to be available

  27. Compared to the .45 auto the 10mm is still a Baby for as how long its been on the market and its never seen combat

  28. I have both a G20 and G21. If both were on a table and I was told to choose one, I am taking the 10mm for that extra power if I need it and it is my choice. If I was left with the 45ACP, would I be upset, no. I have confidence in both rounds to stop anything on two legs, I would just rather have the 10 just a choice and everyone is entitled to choice!

  29. I have them all. 10mm for carry in bear country, 45 ACP for shooting my 1911. and 9mm for EDC.
    We can have more than one caliber.

  30. Are any of you familiar with the Greg Elligritz’s 10 year study of actual shootings? I will post a link in the bottom to a video that discusses this study. But, according to this study, almost ALL popular handgun calibers perform the same. 9mm, 357, 40, 44mag all have an Incapacitation Success rate of 87% while the .45acp had a rate of 86% regardless of rounds fired. In other words, they just looked at whether or not that caliber was able to stop the person in that encounter regardless of rounds fired. Doing a one-shot stop study is impossible because almost nobody fires just one shot. I am a little bit stumped why the .45 didn’t do as well. Maybe it is because people are over-confident in it’s ability and don’t choose the best loads? Anyway, here is a link to the video.

  31. As you likely know, the 10 mm cartridge devolved to the .40 S & W because of weak-gripping and weak-wristed men and women. When the 10mm is gripped and stabilized properly, nothing that you have presented in your article supports your conclusion about the superiority of.45 ACP. Very weird. This tends to undermine your credibility.

  32. With all due respect, this was a silly discussion. I have both calibers and several units of each one, and they clearly have different functions. My choice for day-to-day living, between the two calibers in this comparison, would have to be the .45acp (I actually carry a 9mm). That said, on the highway or in the woods it would be, and is, a 10mm.

    There is NO “one caliber fits all.” That is a myth….just as is the 100% paperless office. Try as they may, paper cannot be totally eliminated, and one caliber cannot be made to do it all. The 45acp and the 10mm are both fine calibers. I shall admit to an affinity for the 45—though it is quite irrational—and that is due to my younger days of being a Jeff Cooper acolyte . Something that, rationally, I can’t shake off.

  33. My comment will come as a reloader, I do not buy factory ammo, and am not aware of what is currently offered for either cartridge. I have shot a number of 10mm auto’s, and have reloaded 10mm ammo. 10mm auto is capable of more than 45 acp +P, but the gap is not that much. I can get an honest 1200 fps with a 200 grain bullet in 10mm auto. In a similar gun with 45 acp, 1100 fps with a 200 grain bullet is not that hard to do. If you compare the 220/230 grain bullets, they are almost identical. One of my favorite 45 loads is a 255 grain SWC, and I can get 900 fps in my 4″ barrel safely. I really doubt 10mm auto is going to beat that. This isn’t even counting 45 super, which is counted as it’s own cartridge, but all it is a 45 acp brass loaded to a more modern 28k PSI.

    For me the big problem is the guns 10mm is offered in. I love the SIG P220, but the 10mm hunter just ruins it. Why did they leave out the double action? You can get all the good full size guns in 45 acp, in nearly any configuration. Recoil for both cartridges are nearly identical

    I’m more a revolver shooter, so I hate picking up semi-auto brass. I’ve tried numerous things, the best is a real big tarp on the ground. Still it seems I manage to loose 10% of my brass from a semi-auto. 10mm brass isn’t cheap or plentiful. You can find 45 acp brass for practically nothing. $50 for 1000 shipped to your door is typical. Bullet cost is a wash. I think a cast bullet is going to be the best for either, but if you like jacketed bullets, 10mm offers better hunting bullets. The 45 acp works quite well for deer hunting loaded with that 255gr SWC I mentioned earlier. I doubt you could ever quantify the differences in damage or penetration between the two cartridges if you loaded each with similar bullets.

    That’s my view anyway. 10mm auto gives you one maybe two extra rounds in a gun, a little extra velocity to be inconsequential in my eyes, and more jacketed hunting bullets if you are into that. All for a much greater ammo and firearm cost, if they even make it in a gun you like.

  34. Of those two it depends but I tend to slightly favor the .45 ACP because there are some caveats with it. With good chamber support you can fire .45 Super, which is more powerful than 10mm. No cartridge sees its full potential unless you handload, which most people don’t do, but the .45 Super can be loaded to over 800-1000 ft-lbs with bullets ranging from 185gr JHP to over 300gr hardcasts. Now to be fair, if just sticking with .45 ACP (+P too) you can still get the old .45 to put out a 230gr JHP over 1100 fps from a 5″ barrel. It’s no slouch and cuts a bigger hole.

    As for 10mm, I’ve had them and I like them but I also think it’s probably the most overrated and overhyped cartridge out there. Again, if using handloads as a way to compare maximum potential, a 10mm can run a 180gr to 1350 fps or a 200gr hardcast to about 1300 fps from a G20 with stock length KKM barrel, not bad. However, I can run those 180gr or 200gr to 1300fps and 1250fps respectively, from a Glock 35 .40 S&W. Nothing alive would know the difference, plus the .40 is cheaper in every metric and it’s simply more efficient than the 10mm is.

    There’s really no need for the 10mm at all, for semi auto handguns you can do anything the 10mm will do with a .40 S&W or .45 ACP, and if you need more power, you’re far better off just going with a .44 Mag on up.

    • You’re comparing running a .40 S&W at significantly higher pressures than what max SAAMI specification permits and comparing that to 10mm ammo that does meet spec to make your argument. I could just as easily compare running a nuclear 10mm load out of a Glock 40 with a KKM barrel to .45 Super ammo at factory specs and be equally stupid for doing so.

      The fact is that running over-pressured ammo out of ANY caliber is just plain stupid regardless of how much chamber support you think you have, but doing so out of a .40 S&W is especially dangerous because not only is the cartridge lacking the necessary case volume to duplicate 10mm ballistics, but it lacks the case wall thickness as well, making it more prone to rupturing in such scenarios.

      Add in the fact that .40 S&W is typically run on 9mm platforms which already causes excessive wear, and the idea of running nuclear loads is even more asinine. Regardless, this discussion (which is long-dead at this point) is supposed to be about the 10mm vs .45 ACP, and that’s a pretty easy win for the 10mm. That said, none of these calibers statistically differ in efficacy against two-legged prey in the absence of other variables (such as barriers or body armor) and are all utterly anemic when compared with rifle calibers, so it’s a pointless argument. Move on.

  35. There are many “cases” that can be made for either caliber. A pistol is firstly a tool. That being said. A tool for what? Self defense: There is no question that either caliber will defend your life against a 2 legged threat. If I had to count on one shot from one caliber firearm to save me from a 2- legged attack give me a 10 MM. If I needed to defending myself from a bear, a boar, a mountain lion or a vicious dog the 10 MM all week long. The best as I can tell you only make two knocks on the 10 MM. Recoil and cost. Ironic that the 10 MM was dismissed because of all groups of people the FBI had difficulty shooting a handgun accurately with the 10 MM Solution: Learn to shoot and practice, practice, practice. Cost? please: load your own rounds and if your joy derived by shooting a lot than don’t take either a .45 or a 10 MM as your primary plinking pistol. Get yourself a .22 RF. Thanks for writing the article. Bill


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