10mm vs. IIIA Body Armor

Commenting on RF’s post about fashion model and gun knowledge supporter Hannah Ferguson, TTAG reader Silphy said she’s thinking of upgrading to 10mm. Reason being? She runs security for an armored truck and transports large quantities of cash, and is looking to up her ballistic advantage from a .38 Special wheelgun. Ideally, she’d like to move to something that will penetrate body armor.

I mentioned that I’d put 10mm Auto’s armor-piercing ability to a quick test while I was on the range, and the results of that can be seen in the video above. Spoiler alert…

IIIA is rated to stop up to .44 Magnum, and 10mm ain’t .44 Magnum. 180 grain FMJ and 220 Hard Cast Lead Flat Nose from Underwood failed to penetrate. Weren’t even close, I don’t believe.

Now, it’s possible that something like the Underwood-loaded 115 grain Xtreme Defender, with its solid copper Lehigh Defense projectile doing 1,700 feet per second, would penetrate. But I still doubt it. I’ll purchase a box and test it, though, if y’all think its chances are good enough.

There’s no real secret to body armor penetration. It’s basically a recipe of high velocity and a slippery projectile that isn’t apt to deform. From a handgun, this typically means small calibers pushed really fast, like 5.7×28. Calibers that break 2,000 fps and are skinny and pointy, making a path through the kevlar weave instead of smashing into it.

To be completely clear here, hollow points are not “cop killer” bullets, despite what “they” want us to believe. For any given caliber, a hollow point is literally the single least likely bullet design to penetrate body armor.

This can present a bit of a catch-22 for someone like Silphy, though, looking to defend an armored truck from an attacker(s) who may or may not be wearing armor.

Hollow points are the best, safest choice for non-armored defense as they are less likely to overpenetrate, less likely to ricochet, and more likely to stop a threat as rapidly as possible. This is why every law enforcement organization in the country uses them. Safety.

But they won’t penetrate armor.

On the other hand, a round made to penetrate armor is more likely to overpenetrate through a non-armored target, likely to ricochet, and probably less likely to cause rapid incapacitation. Bottom line: firing armor-piercing handgun rounds in defense of an armored truck in public poses a greater risk to the public, and is likely less effective against non-armored targets.

I’d probably stick with Tom in Georgia’s suggestion in his reply to Silphy: Mozambique Drill. For me, I’d carry a full-size 9mm with Federal HSTs. Assuming, of course, that I was specifically restricted to carrying only a handgun. What say you?


  1. avatar Omer Baker says:

    Practice your head shots.

    1. avatar uncommon_sense says:

      ^ This!!! Omer beat me to it.

      Note that caliber is pretty much irrelevant if you are going for head shots so you might as well carry a “light” caliber that you can shoot rapidly and accurately. I am thinking 9mm with 115 grain hollow points.

      1. avatar Next Pres picks the Supreme Court says:

        Head shots on a moving target are effectively a myth, hence the reason no serious military or LEO outfit teaches to shoot for the head over center mass.

        Respectfully, that’s not a serious solution.

        1. avatar Katy says:

          On their own, likely not. But in conjunction with Mozambique, your target should be less mobile – even with armor, body hits are going take a moment to shake off. Still not easy, but not as impossible now.

        2. avatar Red in CO says:

          The Mozambique drill is for tactical wannabe operators who just wanna sound cool by saying, “two in the chest and one in the head”. And yeah, headshot are an impractical joke. If you find yourself facing an armored adversary, aim for the pelvis. Seriously, that’s your best bet for a few reasons. First of all, the pelvic bowl supports the entire body. Cripple that with even one good shot, and your attacker loses mobility, which puts him/her at a SIGNIFICANT disadvantage.

          There are also some major blood vessels in that area. Plus, the bowel shape of the pelvis can actually redirect rounds up into the abdomen and chest cavity. So, there’s your answer. Better yet, keep a rifle handy. But if that’s not an option and you have to shoot an armored attacker, go for the pelvis.

        3. avatar Hank says:

          Yup. Especially when your using an old carcano bolt with a POS scope from a book suppository building in Dallas. Just sayin.

        4. avatar Peter says:

          I think you mean “book repository.” At least I HOPE that’s what you mean.

        5. avatar mark s. says:

          Center mass is only an option when you have poorly trained marksmanship and this is complicated by heavier clothing on this area of the target and maybe some form of armor also . Groin and gut , head and neck , are obviously the most productive for killing , not necessarily the outcome that the LEC want . Their goal is incapacitation , my goal my be something different . I am a head and neck , groin and gut shooter , and low caliber high velocity on target , is my choice of personal protection.

        6. avatar mark s. says:

          I’m with Red , +1
          Any careful study of the human anatomy and a conversation with an ER Trauma surgeon will confirm his points .

        7. avatar Stuki Moi says:

          If you put led lights on people and have them flail around in the dark, you quickly realize why everyone in the business of killing or being killed, are taught to aim for COM. It’s literally an oasis of calm, with every other bodypart erratically orbiting around it.

          Even people who think they are running from side to side, Western style, to make themselves a harder target when running for cover, is mostly rotating their legs and feet from the left of COM, to the right of COM and back, repeatedly. With their head doing the same dance, 180 degrees out of phase. While COM stays still enough to remain a relatively high probability target for the marksman who knows to disregard the noise of the peripheral parts flailing around. The “escapers” who do it right, (meaning really moving COM meaningfully left and right) are well aware their direction changes will almost double the time it takes to reach the cover they are running for. Making doing so in a proper fashion, a non obvious choice vs running as fast as one can in a straight line.

          The best illustration I have heard, is aiming for COM is like aiming for the center of a propeller, vs trying to hit one of the spinning blades….

    2. avatar Big Daddy says:

      Wow I’m no expert but most of you guys don’t know what y’all talkin’ bout.

  2. avatar David says:

    Would love to see the 10mm Underwood Extreme Penetrator and Defender tested. Another cool option would be to get an aftermarket barrel in 9×25 Dillon and test the Underwood offerings.

    1. avatar Jeremy S. says:

      Yeah, I think some 9×25 Dillon rounds would have an even better chance (smaller diameter and faster). I’ll look into trying that.

  3. Liberty 10mm might stand somewhat of a chance of going through that body armor, although I can’t say whether it would expand/fragment once it’s done so. It’s rated at 2400 fps. But the sectional density isn’t in favor of it making it through, and even if it did, I don’t know what it’d look like if it got through the armor; it might smash its nose and turn into effectively an FMJ, but even so, at such light weight (60 grains) it’d pose less hazard to folks downrange than a regular 10mm FMJ (at 180 grains).

    DXK did a test with Liberty .45, .40 and 9mm, and none of them got through their IIIA plate. The 10mm is notably faster than those, but it still remains iffy.

    If you want a handgun that can go through a vest, a .454 Casull will do it. In my test of the Engarde vest, the Raging Judge with a 1900 fps Hornady 240gr went right through it like butter. But that’s about the only thing I tested that got through it, short of a rifle.

    1. avatar PeterK says:

      As always, your insight is super awesome.

  4. avatar other chris says:

    7.62×25? Not that you can get a quality 15 round+ gun for it.

    1. avatar JJT says:

      7.62X25tokarev, you betcha

  5. avatar Next Pres picks the Supreme Court says:

    The 10MM Lehigh Penatrators will definitely defeat level II-A kevlar. Not surprising, but it beats 38SPL from that standpoint.

    I have a sneaking suspicion they would also defeat LVL II armor – which would account for the majority of soft armor out on the market today.

  6. avatar Ralph says:

    See the Liberty 9mm ammo video.
    Level 3 armor shot with Liberty 50grain 9mm round traveling at 2,000+ fps.

    Jump to time stamp 02:24 for the actual test using a SIG P226

    1. avatar Next Pres picks the Supreme Court says:

      Holy SH*T! Use one of those in every 3rd in your mag, and you’re all set for terrorist threats wearing soft armor..

      1. avatar mark s. says:

        I load speed / expansion in all my magazines already , 3 max. expanders one HV or FMJ-HV . I know all the arguments against this so no reason to argue with me . I’ve been a handgun shooter/trainer for 25 plus years and it just works for me . I understand the legalities and potentials of pass through but I will just deal with it . I never advise anyone else what they should load their firearm with , I only provide the information and training .

    2. avatar Accur81 says:

      I was going to say the same thing.

      However, I load .40 Smith Ranger 180 grain JHP and Federel HST 9mm + P 124 grain and Federal 00 buck in my SD guns. None of those will penetrate a good vest. Want a round that zips through IIIA Kevlar without over penetrating? The good ‘ol M193 5.56 55 grain FMJ – from a rifle. Possibly a pistol, too, if the barrel is long enough and the range is short enough.

  7. avatar TheOtherDavid says:

    I love my 10mm but if you’re going to use it as a daily carry firearm it certainly demands more regular practice.

    One benefit of a good 10mm JHP in this case might be that while it may not penetrate, you’ll get more energy transfer and therefore I’d expect more blunt force trauma hitting a vest with a “real” 10mm vs a 9 or 40

  8. avatar jwm says:

    If you’re restricted to a handgun and you’re carrying openly on a duty belt then you go for a full size 9mm service pistol with a 15+ round carry capacity. Carry 3 mags as spares and practice reloads. A j frame in your load out might also be good as a back up.

    Your biggest worry about an armored delivery truck isn’t body armor, unless they’re wearing a tank arms, legs head, etc. will be exposed. Your biggest threat will be numbers. The bad guy ain’t coming alone.

    In this exact scenario quantity has a real quality.

  9. avatar ActionPhysicalMan says:

    My 45gr 5.7s tumble twice and consistently penetrate 14-15″ of gel after penetrating IIIA. They penetrate 16-17″ of gel if there is no armor. The tumbles are at 4-7″ and 9-12″. They are 1.5-2″ at the widest but rather two dimensional. I’d have to scientifically shoot a bunch of prisoners or something to say if this was enough damage to be relied upon for defense. It’s loud, at least, for sure though.

    1. avatar Next Pres picks the Supreme Court says:

      Out of a carbine ~16IN barrel, sure; but not out of a ~5IN barrel pistol they don’t. Not unless you have the restricted rounds specifically built for AP.

      5.7 is a cool idea, but the lack of effective ammo on the civilian market killed it pretty dead for most.

      1. avatar ActionPhysicalMan says:

        Most commercial ammo for the 5.7 does suck, true enough. Elite ammo does not though and a few of their loads will easily defeat IIIA armor with a 4.8″ barrel. I have a 6″ barrel and load my own. They are not lead. Others with similar loads report that they have penetrated 3 IIIA panels and then done damage to a target. The 5.7 is one of those cartridges that really benefit from hand loading. One has to do their homework and be quite diligent or they will experience malfunctions or worse.

      2. avatar ActionPhysicalMan says:

        Being a bit touchy here, but you should have noticed that I said my bullets were 45gr and that realized that none of the widely available commercial loads are 45gr, so I obviously wasn’t talking about the standard fare. This matters because you implied that I was presenting carbine results in a handgun discussion.

  10. avatar Cliff H says:

    Any pistol caliber will defeat body armor of any level, including IIIA. There is a simple trick, alluded to in some of the comments above – DON’T SHOOT THE DAMN VEST!

    While shots to “Center Mass” are the Holy Grail, if you even suspect the guy is wearing armor, why are you wasting your time and ammo shooting the vest? Head, arms, shoulders, groin, legs. That vest covers at best 30% of the body.

    My best advice (I am NOT an operator), carry a semi-auto of whatever flavor or caliber you prefer. A double stacked 9mm sounds about right. In an encounter put a shot center mass to get his attention, then begin emptying your magazine at every exposed body part below the level of the vest. Any hit in this area is very likely to put him on the ground and make your follow up shots easier and his ability to respond before he bleeds out much more difficult. As a bonus keep in mind that if he winds up on his back the sides of a Kevlar vest are seldom as resistant as the front and back, and usually no plates.


  11. avatar Oregon Cannoneer says:

    .22 TCM for the win,

  12. avatar Sean says:

    Or upgrade to .357? Similar mechanics that this person is used to but around 10mm ballistics!

  13. avatar strych9 says:

    I’d say the same thing I said when the question was asked.

    Go through the checklist I provided. The guns not filtered out are in contention for your carry piece. Now pick the one you like the most.

  14. avatar Adub says:

    If a robber has planned enough to wear body armor, they’ve probably planned enough to wear a steel plate AND carry a rifle AND have a second shooter.

    At that point, you’re trying to plan a contingency for Dracula riding Godzilla.

  15. avatar ButtHurtz says:

    45 super or go home, sissy

  16. avatar billy-bob says:

    AR pistol?

  17. avatar Silphy says:

    I greatly appreciate the video and analysis! As well as the advice. upon reviewing what’s been said here, shown, and discussion with my boss, we’ve kind of come to the conclusion that we’re gonna work at adding a third person to the route, and giving him a shotgun as guard. We’re also being issued personalized body armor. I also went to my local gunrange and rented a handful of guns from .25acp (They threw that rental in free) up to .460 XVR. (Resisted the urge to test out the 50AE DEagle they had) Ultimately, I’ve narrowed it down to either a gen 3 glock 20, or a CZ-p09. It is good to know that my boss actually listens to my concerns, what with the uptick of violent crimes in my city. The only reason the glock 20’s still on my list is because I can pick it up for pretty much the same as the CZ. We got to talking, and yeah, the over penetration was brought up as a major issue with what I was looking at and thinking about. Decided that the better option besides constant work on target practice (something I now do religiously every saturday) was to get a round that hits hard.

    1. avatar Jeremy S. says:

      P-09 is a nice gun. With the factory +2 basepads you have 21+1 rounds of capacity. That’s pretty intense.

      Does the G20 fit in your hand okay? It’s a chunky gun. If you can’t find or do a Gen4, I’m sure you could find a Gen3 SF. The SF frame is easier to get a full, controllable grip on.

  18. avatar Accur81 says:

    I worked for Dunbar Armored for almost 2 years. We qualified once in that time, and most of my coworkers were shockingly bad at shooting. I upgraded my gun from a .38 revolver to a Glock 35 Gen 3. My advice is to get a good full sized 9mm and a lot of practice. The 10mm is not good for new shooters.

  19. avatar Hank says:

    .460 Rowland

  20. avatar Lhshtr. says:

    Well if it comes at me with a vest, I just use my ccw, my “5.7×28”. Carry 20 or 30 rounds two mags and shoot him in his D _ _ _ or P _ _ _ _ _. the rounds fly around 2,200 fps. end of day for the as_ hole. Now thats a shooter. Carry like you cary a glock 19. At a 100 yds. it flys flat, straight and true. Hit target in same area and he will go down… Be safe out there.

  21. avatar Bill says:

    Trade in your lead for sodium. Won’t penetrate very well, but….

  22. avatar Matt Matteson says:

    I’d go with a hot bonded .357 Sig. While you’re not going to penetrate quality armor, you should penetrate, significantly deform, or well-thump any soft panels on the market. More importantly, this is the go-to round for barrier penetration, whether this is auto-glass, ATM sheet metal, or park-bench plastic. Most importantly, whether you’re an FBI penetration fetishist or a Border Patrol energy junkie, .357 Sig exceeds all standards from a 4.5″ barrel.

    It’s not fun to be shot in the chest, and unlike the videos where people take a baseball bat to a clothed jug, the reality is more like being hit with a lead golf-ball. The more energy you can dump into the fabric, the better your chances of having an effect. If you’re stuck with a handgun…

    Whatever you do, be sure you can control it. All calibers come in very manageable platforms, it’s just a question of how big and heavy a pistol you’re willing to adopt. .357 Sig is arguably the best of modern manageable cartridges, just know that every trigger pull brings a healthy blast to your senses and budget.

    Stay Safe, ~MM

  23. avatar Aaron M. Walker says:

    Ray gun….set to disintegration…

  24. avatar Libertarian says:

    10mm and 460 Rowland are hangun calibers thats seperates the boys from the real men”s 🙂

    1. avatar ActionPhysicalMan says:

      Hmmm, why would you want to separate them?;-)

  25. avatar Shrike30 says:

    Your boss approving a long gun that doesn’t punch body armor (shotgun) doesn’t sound like he understands the situation you’re concerned about. It would make a lot more sense to have your third running something like an AR-15 (for lower costs) or a Tavor (more maneuverable in/out of a vehicle); a 5.56mm rifle is a lot more precise than a shotgun, you’ve got less risk of stray shots/pellets causing problems for bystanders, and 5.56mm just ignores soft body armor.

    If you’re shooting at someone with a handgun and not penetrating their vest, you’re only punching them in their padded chest as hard as that gun kicks back in your hand. It doesn’t make any sense to carry a hot/fast round like .357 Sig or 10mm Auto if you’re not going to punch their armor with it… all that does is make the gun kick a little harder and slow down your followup shots between poking pistol-caliber holes in someone.

    If you can afford/run something like a Five-seveN, that would get around the armor problem. If not, stick with something “lethal enough” like a 9mm, and just keep rolling your targeting between the sternum, the eyes, and the pelvic girdle. The vest only protects the thorax.

  26. avatar Jimmy Mullin says:

    New Underwoodammo.com 357 Sig load [email protected] 2,100 FPS MV.That should handle class3A.For the 10mm try Libertyammo.com [email protected] 2,400 FPS MV.The 500 mag,454 Casull and 44 mag all have full metal jacket loads on the market.My two M57 Zastava pistols are loaded with PriviPartizan,Wolf or Sellier and B ammo,7.62×25 brass cased boxer primed,buy from Cheaperthandirt.com Ammunitiontogo.com or Luckygunner.com Jim

  27. avatar Jimmy Mullin says:

    I carry pepper spray/Teargas/UV dye spray from MACE……I also sometimes carry the KaBar 1271 fighting knife ( buy it from Amazon for a decent price ),why the knife? It’s legal to carry in my state and I trained for some 20 years,karate-kung fu fighting with knives,sai,katana and Bo,so,why not.The 1271 is well balanced,light,maneuverable and sturdy.Get one,if they are legal in your area.I used to carry two spare mags,but the last few years,i’ve only carried what’s in the pistol.Today’s pistol is the Ruger American pistol 9mm loaded with Libertyammo.com [email protected] 2,000 FPS MV.

  28. avatar Craig says:

    For your specific situation I would just upgrade your 38 to 357mag with handloads. Out of my Taurus with a 6in barrel I can push 180gr hollow points over 1500fps with w296 powder. It won’t penetrate armor but it will definitely still shatter their sternum/ribs and without armor nobody is taking more than one shot to go down. At the same time I can get the 125gr hollow points over 1900fps with the w296 powder again will not penetrate armor but with that much energy transfer your are looking at shattered sturnum/ribs with armor and soup for internal organs without. Neither round shows any signs of over pressure. That all being said I could see a possibility if you could find a light maybe a solid copper or brass bullet maybe about 115gr with a sharp pointed nose, get that moving at the 2000fps mark maybe just maybe you could get armor penetration

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