10mm gel test: Hornady 175 gr Critical Duty FlexLock

We fired 10mm Hornady 175 gr Critical Duty FlexLock from 4.5″ barrel EAA polymer frame Witness at 20 feet into clear ballistic gel to assess velocity, penetration, expansion, and weight retention. While the performance may not be perfect, it is nevertheless quite good.

Average velocity: 1,083 fps
Average penetration: 18.7″
Average retained weight: 174.0 gr
Average max expansion: 0.657″
Average min expansion: 0.484″

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Transcript ….

[coming soon]


Andrew is a combat veteran of OEF and has performed hundreds of ballistic tests for his YouTube channel, The Chopping Block (https://www.youtube.com/user/chopinbloc). He is an avid firearm collector and competitor and lives with his family in Arizona. If you have any questions, you may email him at choppingblocktests@gmail.com


  • Haulin’ Oats

    Nuclear 10mm is perfect for a PDW or SBR (SIG MPX please!) like the KRISS VECTOR in 10mm.

  • gunsandrockets

    If selecting Hornady Critical Duty ammo, there seems no practical terminal ballistics advantage to picking 10mm vs .45 ACP or .40 S&W. WTH?

    • PK

      Most 10mm in the USA is downloaded to be marginally better than .40S&W, in my experience. It seems to mirror how underloaded a lot of European cartridges are when purchased from companies in the USA, but who knows why.

      • Dr. Longfellow Buchenrad

        That and the fact that gel is somewhat ok for comparing (but not calculating) soft medium penetration (like fat and muscle), but not all bullets behave the same way when encountering bone and harder tissues.

      • valorius

        Liability. Thank the lawyers.

  • Scott Willbanks

    a 40S&W pushes a 180gr bullet roughly 980fps. What happened here that a 10mm couldn’t do any better than 100fps faster with a lighter bullet?

    • Nandor

      The most likely reality is that they didn’t want to pay to research a .40 cal bullet that would expand at real 10mm velocities. They added a pinch more powder to the .40 s&w loading and called it a day. I’ve seen tnoutdoors do real hot 10mm load gel tests and it’s clear the .40 bullets don’t expand well when going too fast, just like when they go too slow.

      • Dr. Longfellow Buchenrad

        I would argue that when using an expanding bullet, there isnt much that .40 cant do that 10mm can. The magic of 10mm is using a heavy hard cast penetrator with an obscene amount of powder behind it. Otherwise just shoot .40S&W.

        • Nandor

          Agreed. I’ve seen videos of 10mm taking down animals as big as a moose with a single shot. That said, we’re nowhere near as big as a moose so it’s wasted on and in some cases won’t have as good effect on humans.

  • USMC03Vet

    10mm Weak & Weak!

    Hornady makes some truly pitiful ammo.

    • Dr. Longfellow Buchenrad

      Yes if youre shooting 175s out of a 10mm, mv better be at least 1200.

  • missourisam

    Many years ago after being involved in a shooting, and finding that even a .357 was not the ideal cartridge to stop a man, I went to a .45 ACP with 185 grain hollow point at 1200 feet per second, Granted they were hot, and I went to a 22 pound recoil spring and a recoil plug that a gunsmith was building that had a strong spring the last 3/8 inch of the slide travel. I used it to hunt mule deer with, and if I did my part at under 35 yards every shot was a one shot kill. Since then I’ve seen no reason to change, although I now hunt with a .45 Colt with 250 grain hollow point ammo at 1300 plus FPS. That doubles as a bear load, or if I should run into a small elephant that is pissed off. Not something that you enjoy shooting all day long, but it is tolerable.

    • No one


      Aside from the fact that’s It’s actually illegal to hunt deer with .45 ACP in quite a few states, I can’t think of what backwards logic you used to assume that .45 ACP has even close to the same terminal effectiveness against either Men or Small-Medium sized animals then even moderately loaded .357 Magnum, let alone true full power loads like Buffalo Bore, Double Tap or Underwood put out.

      It’s not even remotely a comparison, .357 completely blows .45 ACP out the water and sends it running home to it’s mom after it hits the beach.

      • iksnilol

        But .45 is so much larger. It’ll totes magotes kill the soul of tihngs you shoot.

      • ozzallos .

        Weight is weight. People don’t seem to realize that. Remove enough and what you have left is a light round that competes in the 357 territory driven by more case capacity. Or even, yes, 10mm.

        • No one

          .45 ACP case capacity – 25gr of water.

          .357 Magnum case capacity – 26.2gr of water (The fact .357 is specifically designed for bullet types with a wide Meplat to take up less volume in the case itself tends to also help with this.)

          Or, something better!

          .45 ACP Maximum approved pressure – 21,000 PSI (23,000 for +P)

          .357 Magnum Maximum approved pressure – 35,000 PSI

          …..I’m sorry, what was that you were saying about case capacity again and when did I mention 10mm Auto in that post?

  • 22winmag

    I will stick with my 2,400fps explosively fragmenting 10mm ammo. Velocity kills. Thanks you, that is all.

    • Wordmahn

      I’m with 22winmag. 16 rounds of DoubleTap 135 grain load through my 10 mm Glock would be my choice if I had to face down a room full of really pissed-off, 300 pound bikers and couldn’t bring a long gun. Those things flat zing, would penetrate plenty and be explosive. Even so, I’d much prefer 30 rounds of 77 grain TMK through my SBR.

    • No one

      It’s a good thing those incredibly overpriced rounds have enough sectional density to back up said “explosively fragmenting” rounds to cause effects like temporary cavity tearing, remote wounding effects and deep tissue penetration like a fragmenting rifle round does! Or will penetrate deep enough in an average attacker so they’re more effective then your typical good quality JHP!

      …..Oh wait, they still don’t? And JHPs are still superior for pistol self defense use? Sorry to hear Liberty still has you on their brand of Kool Aid I guess, maybe some day you’ll pick up a book about actual ballistics.

      • valorius

        At what velocity do you suppose those wounding effects occur?

        • No one

          Depends on the projectile type but, usually, 2,700 fps is the benchmark for causing flesh and muscle in a temporary would cavity to rip and tear free in someone with the physiology of a human.

          This is typically also seen with rifle rounds which, as you may know, have much better sectional density on projectiles, and in particular rounds that fragment at high velocities in rifles, these are dense enough to actually penetrate deep enough to cause severe wounding from the fragments themselves instead of just stopping very early in. (I could show you actual X rays of flesh and bone hit with fragmenting 5.56mm rounds for example but….It wouldn’t be pretty.)

          • valorius

            Actual xrays would be quite illuminating. Get it? 😀

          • valorius

            So .30-30, .300 blackout, and Ak 7.62 exhibit none of those wounding characteristics?

    • valorius

      How much do the projectiles weigh?

      • No one

        Literally 60 grains, they have no sectional density at all which makes they’re actual performance in tissue incredibly overhyped.

  • Isn’t barely-a-thousand with a 175gr bullet kindasorta super anemic for a 10mm? I’m used to hearing the caliber mentioned in the context of molesting bears, not bothering mosquitos.

    • 277Volt

      Definitely anemic. Underwood Ammo pushes a 180 gr. Gold Dot to 1,300 fps.

  • FT_Ward

    It seems that the “experts” (the FBI) have decided that ~ 18 inches of penetration of gel is the maximum allowable for a self defence load. That would explain downloading a 10mm.

    I suspect the 18 inch standard was hit upon to ensure the “best” handgun round didn’t turn out to by something the FBI couldn’t get the vast majority of it’s members to shoot- a hot .45 ACP or 10mm.

    The idea that penetration over 18 inches is bad also does wonders for the bullet manufacturers as it encourages the sales of various expanding bullets.

    • No one

      The 18″ Limit was put in place because at that point and past it are where rounds will risk exiting the target and potentially hitting a bystander.

      It’s incredibly rare, but it can happen.

      • FT_Ward

        That’s the story but it’s bunk. Most rounds fired miss. If the expanding bullets are actually more lethal then the chances one of the misses will kill an innocent person is increased. The gel tests ignore the need to good through intervening materials.

        If the head of a police force says (as they all do) “We will give our officers the best equipment to keep them safe…” and you’ve found the “best” handgun round to be a full house 10mm you’ve got a problem because you’re also committed to “diversity” in hiring. Q: What to do? A: Pretend that you’re so concerned about bullets going through felons and harming an innocent that you’ve found a “maximum” level of performance for handgun bullets. At the same time you put AR-15s on general issue because recoil isn’t a diversity issue with them.

        WRT the rarity of events. Which happens more: a police bullet goes through the torso of a felon and harms an innocent person or a police bullet is going towards a felons vital organs and is stopped by an intermediate material- clothing, drywall, door jams, car doors, glass, bone etc?

        BTW I wonder how much energy a pistol bullet, which has gone through 18 inches of people, has to harm anyone else? If a bullet which has the capacity to go through 21 inches of gel goes through 18 inches and then flies another 10 feet and hits another block of gel how far will it penetrate? No more than 3 inches and probably less. So how dangerous is it? The problem can’t really be bullets going beyond 18 inches can it? The game was to remove 10mm and .45 ACP and most FMJs from consideration while showing 9mm and .40 HPs were OK.

        • iksnilol

          Uhm… you do know that a bullet missing is sorta the point behind hollow points? Like, if I load up my Tokarev with some screaming armor piercing copper rounds and I miss? That sucker is going through a city block.

          A hollow point though? It hits a building, doesn’t go farther.

          EDIT: Sorry to disappoint you ,there’s no anti 10mm/45 acp conspiracy. It’s just those cartridge suck for most use.

          • FT_Ward

            Will a .45 ACP FMJ will go through city blocks? Don’t bother answering 7.62 Tokarev won’t either. They’re pistols.

            No conspiracy? Explain .40 S&W. 10mm won the FBI trials but since very few agents wanted to shoot it out came a downloaded 10mm. Now departments are discovering 9mm again for the same reason- diversity. All the stuff about protecting innocents is bunk. It’s about finding a gun/caliber combination that the vast majority of officers will practice with enough to pass qualification shoots.

          • iksnilol

            No, again, no conspiracy. Even Jerry Miculek shoots better with a 9mm than with a .45.

            Considering most houses are plywood and air, it isn’t much of an exagaration to be honest. A regular FMJ will go through more than a dozen walls.

          • mosinman

            do you have any proof of Jerry shooting better with 9mm as opposed to .45? because he seems to shoot everything extremely well

          • iksnilol

            That’s my point. He shoots everything good, so you are basically taking the shooter out of the equation. And then simple physics win out, since a 9mm vs a .45 has waaay less bolt thrust, it’s faster to shoot (and thus faster to shoot accurately). Same thing would happen once again if you gave him a 5.7mm vs a 9mm.

            Though if you want some semblance of proof. He does prefer a .357 over a .44. (which is basically the revolver equivalent of 9mm vs .45)

          • mosinman

            If .45 was so unmanageable wouldn’t you see a drop in performance on his part? You really don’t. I’ve shot both and they’re both easy to handle and I don’t notice much difference in recoil. Of course I’m firing both cartridges out of all steel handguns so that helps too. I’m also not firing +P ammo either so maybe you’d see a difference there

          • iksnilol

            I didn’t say it was unmanageable. Just that even Jerry Miculek shoots better with a nina over a fo-five.

          • mosinman
          • iksnilol

            Then you’re doubting physics.

          • mosinman

            If we were comparing cartridges in a vacuum you’d be right. But we aren’t. For example, if a Kriss smg in .45 was more controllable and softer shooting than say, the Bizon in 9mm is the Kriss breaking physics? Obviously not. Or let’s say you’ve got a lightweight polymer 9mm revolver and you shot it against an all steel full-size .45 automatic pistol , will the .45 recoil harder just because it’s a .45 and fires a larger heavier bullet? Or will the lightweight polymer framed revolver be the harder recoiling pistol?

          • iksnilol

            Now you’re moving goalposts, I thought I was being clear that all else being equal the smaller caliber is more controllable.

          • mosinman

            not really. you basically said that .45 is harder recoiling simply because it is larger

          • iksnilol

            And that is true. Again, despite the heavier weights and ports of a regular .44 revolver, it still recoils more than an unported lighter .357.

            Sure, you argue semantics (with recoil reducing oddball systems such as the Vektor) just to be difficult. That was surprising but not entirely unexpected to be honest.

          • mosinman

            and the gap between .44 magnum and .357 magnum is much larger than .45 and 9mm of course .357 recoils harder than a .45 even though it uses lighter bullets of a smaller diameter 😉

          • iksnilol

            Percentage wise, the gap isn’t as large as you think. About 50-70% energy increase and a wider diameter.

          • mosinman

            I forgot that a 50% to 70% energy increase is minimal

          • valorius

            Stop making things up.

          • iksnilol

            Not making things up, dude set a faster world record with a .357 (or was it actually a 9mm revolver) than he did with a .44 magnum.

            So yeah, sorry reality doesn’t conform to your fantasies. An cartridge that’s easier to shoot and that you can carry more of is *shockingly* more effective no matter who uses it (now where did we face that conundrum earlier?).

          • valorius

            .44 magnum recoils far more heavily. The diff between the recoil of 9mm and .45 acp is negligible.

            He also set a world record for speed firing a .50 cal barret m82, btw.

          • iksnilol

            I know, but a .45 has higher bolt thrust than a 9mm.

            So yeah, theere’s a difference.

          • valorius

            Ummm, you’re missing his point entirely.

        • valorius

          I carry DEEP penetrating flat points in my .380 for the very reasons you list in this post.

      • valorius

        I’ve never heard or read of a single incidence of it happening.

  • While I agree that the current loadings for 10mm are underpowered it’s not without reason. When Colt first released the Delta Elite I ran out and bought one. The only ammo available at the time was the Norma load which was loaded very hot. Over time those who shot the Delta Elite a great deal started having cracked slides. That said when other companies started loading for it they backed down the load a bit and that seems to have continued over the years until most loads are rather weak. There are some pretty warm loads out there you just have to look for them.
    By the way I never had trouble with my Delta Elite but I didn’t shoot thousands of rounds through it.

    • Judging from “Bren Ten – The Heir Apparent,” the original specifications for the 10mm cartridge fell victim to a weird game of escalation between Cooper, Dornaus & Dixon, and Norma. The original goal was to meet Cooper’s ideal standard of .40/200 gr/1,000 fps. Then Cooper suggested that D&D bump it up to 1,100 fps at the muzzle so that the impact velocity would be guaranteed to achieve 1,000 fps at long range. Once the concept of a compact Bren Ten was floated, Cooper then increased his recommended velocity to 1,150 fps so that even the short barrel models could meet the 1,000 fps threshold at long range. When it came time to send the specifications to Norma, Mike Dixon increased it yet again to 1,200 fps, apparently assuming that Norma’s test barrels would clock faster than the factory pistol barrels. Norma seems to have added their own fudge factor, and bumped the velocity of the earliest lot even higher.

  • aka_mythos

    I want that “super manly” 10mm with all the muzzle flash for a carbine…

    • GaryOlson

      Your 10mm PCC needs to be paired with a properly matching pistol. Glock is not an option I would choose for a properly loaded 10mm round. Does CZ make a 10mm pistol yet? Or PCC?

      • aka_mythos

        I’d want it for a carbine. All the 9mm and .45 carbines are more material and weapon than necessary… both cartridges reach a point where they’ve efficiently generated power and stabilized bullet with a sub-7 inch barrels. All that extra barrel length doesn’t do much if anything for the bullet. Besides the 16 inch barrel length required under the law, the next most common barrel length of a carbine style weapon is 10 to 11 inches. The three most common cartridges that reach peak efficiency in a 10 to 11 inch barrel length 5.7×28, full pressure 10mm, .357 SIG, 300blk. In these calibers it is a more holistic solution to the emerging carbine paradigm.

      • No one

        As someone who owns a G40 and feeds it basically nothing but Buffalo Bore and Underwood rounds, I’d like to tell you that you’re wrong about Glock pistols somehow not being about to handle “Properly Loaded 10mm”.

  • BBMW

    To answer your last question, maybe it’s because all 10mm bullets now are designed to be used in .40 load for .40 velocities. At 10mm velocities, they lose effectiveness by fragmenting and/or overexpanding (meaning peeling back so that their expanded diameter is less than it would be if fired at the velocity the bullet was designed for.)

    There isn’t enough demand for full power 10mm rounds to justify making 10mm bullets designed to work correctly at pull power velocities.

  • Raptor Fred

    Well here are some of Hornadys results with this 175gr loading in both 10mm and 40. Almost identical. But certainly different than the results found here in clear gel.


  • valorius

    1080fps, it might as well be .40 S&W. What a wimpy load.

  • valorius

    What’s with Hornady using all these goofy non standard weights in their critical duty line, in every caliber?

    • No one

      It has to do with the weird way their flex lock cored bullets are actually designed.

      • valorius

        Unless i’m mistaken (dont feel like looking it up), all their Critical defense rounds are of a standard weight. I could be wrong but it sure seems to me like Hornady just wants to be different.