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As ammo goes, 9mm is a high-pressure round and 9mm +P is, naturally enough, even higher. DoubleTap loads their ammo generally towards the hotter end of the spectrum. So what happens when DoubleTap loads up a 115-grain 9mm +P round?  They claim a scorching 1,395 feet per second from a 4″ barrel. For comparison, CorBon’s 115-grain +P DPX is rated at 1,250 fps and Barnes’ TAC-XP 115-grain +P round 1,100 fps.  Now, a 3″ barrel won’t deliver quite that much velocity, but — what will it do? And how does it perform? Due to the generosity of one of his viewers, STB410 got a chance to find out.



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  1. You see this frequently – faster not always better. I’ve seen some 10mm Gold Dot loads where the round just blows apart, same thing with some hot Hornady XTP rounds – each bullet has a sweet spot for velocity.

    I think that’s one reason I continue to be impressed with the Federal HST rounds, the seem to have good penetration and expansion at different bullet weights and from different barrel lengths. Whether it’s out of a G26 or a G17 I feel confident that I’ll get good penetration and expansion, without worrying about needing a “short barrel” version of the ammo.

    Thanks STB for your continued great vids!

  2. STB has quickly become my favorite ammo reviewer. Thanks for another great video.

    • Yup, same here. And when customers buy the little 3″ guns, I send them straight to his channel to see the difference that short barrel makes in ammo performance.

      Especially when they ask for the Critical Duty.

  3. I love the “straight-up” data! Consistent testing methodology, great empirical results.

  4. I’d really like some to clarify, in the context of a self defense shooting against a human being, how core/ jacket separation even matters… Sounds like more wound channels to me. I’m pretty sure an average sized human being shot with this load would be pretty dead.

    • Look to hunting experience as a guide. Bullet weight retention is an oft used metric for reliable performance.

      A bullet design that is prone to coming apart at the expected impact velocity may work; it may not. It’s not a given. (Well, strictly speaking, less of a given).

      Think about it this way: the energy that is used in fragmenting the bullet is NOT used to destroy tissue. The tearing of metal is a ‘sink’ of energy that can not be recovered.

      So, yeah, you might get a separate wound channel, but the question then becomes is the combined total destroyed tissue volume smaller or larger than what would happen if the bullet stayed together.

      Big game hunters don’t use frangible fragmentable bullets for a reason.

      • Good analogy. And in the self-defense area, where the pendulum keeps swinging back and forth between expansion and penetration, it seems that penetration is back as the bigger factor in reliable self-defense ammo.

        The denim testing rounds for this video looked great – but under a foot of penetration? If they had to go through outer clothing/arm/side entry/etc….too many variables there to allow for that shallow a level of penetration in an EDC self defense round.

        • The issue with this bullet is, it didn’t totally frag out. It lost it’s jacket deep into the gel, with the core, at or around the same penetration distance. Plus, it held together through the intermediate denim and penetrated arguable slightly deeper. I really think that this looks like a bullet that is going to perform better under realistic conditions with intermediary bone and clothing to slow it down. You see a similar effect with Winchester segmented slugs. They blow apart in gel, and then just gold together and expand if they hit something hard to swage the projectile together…

      • “Think about it this way: the energy that is used in fragmenting the bullet is NOT used to destroy tissue. The tearing of metal is a ‘sink’ of energy that can not be recovered.”

        I think you’re missing something here. It’s the bullet that contains the energy, not the flesh it penetrates. The flesh has 3 ways of absorbing that energy, destruction, damage and deflection. A major league fastball has about the same energy as a .22LR fired from a handgun. When a pitcher hits a batter in the ribs that energy is entirely absorbed by tissue damage (bruising) and deflection, even if a rib is cracked that’s still damage not destruction. But the .22’s energy is mostly absorbed by tissue destruction in which you have a deep path of total destruction, albeit narrow in diameter. Since our vital organs are contained deep within our bodies, I’d rather take the fastball, but in either case the energy is absorbed by the body. The only way for the bullet to fragment is for the energy in that bullet to be absorbed by the flesh (the same can be said for normal bullet expansion).

        The problem with this round is penetration. It would be a devastating round if the round is taken straight into the chest. That’s about 420lb/ft. of energy from that little 3″ pistol, and every pound of it will be absorbed by the flesh, and anyone standing behind the victim/assailant needn’t worry about any of that energy being absorbed by their flesh. If however, the bullet must travel through the arms or some odd angle it will not penetrate enough to reach the vital organs. Those organs are much closer to the surface though than they are in an 800 pound elk, and your odds of needing a quartering away shot in a self defense situation is very low.

        I’d also add that you should put more stock in the denim tests because the denim sort of represents the skin when a bullet impacts it. But this round fails because it over loads the bullet, there’s no getting around that. It would be even worse from a 4″+ barrel. Too much fastball, not enough .22.

        • Huh?

          Where does the energy come from that tears the bullet up?

          It’s the kinetic energy of the bullet. if that energy is being used to fragment the bullet, it is not used to destroy tissue.

          Sorry; I did not read your post past “you are missing something, the energy is not in the tissue.”

          I never said it was.

        • And you are missing the physics that come with fragmentation. If a bullet loses weight it loses energy. Speed times mass equals energy. If it loses mass it loses energy and that means it is going to penetrate less.

        • The bullet does not lose energy because it breaks up, it loses energy more quickly by breaking up. There is nothing to expend that energy on except the flesh the bullet encounters. That’s the whole point. A bullet cannot expand, deform or break up unless it dumps that energy into the body it encounters. Without resistance the bullet will continue off to forever wander the limitless bounds of space. If two bullets with equal energy enter a body that is 12′ thick carrying the same amount of energy and one of them stops in 8″ and the other passes through the body still carrying 25% of it’s energy, in which case has the body absorbed more energy? Expending a bullet’s energy too quickly leads to under-penetration, expending it too slowly leads to over-penetration. How that energy is expended isn’t nearly as relevant.

          And JR, read the rest of the post and you might understand what you’re missing. Then I’d welcome your comment.

        • “The bullet does not lose energy because it breaks up, it loses energy more quickly by breaking up. “


          Look. I’m not missing anything. I’ve been doing this kind of thing professionally for over 20 years. I pretty well understand the mechanics of fragmentation and tissue destruction. Been a hunter, been to autopsies and have conducted private sector research in the ballistics fields.

          I’m not reading a long post that is at best trying to address something I did not say.

          This is why I “love” the Internet. A dude asked a question. I tried to give a concise, non-dissertation-esque answer in non-overly technical terms to convey an IDEA.

          And out comes all the irrelevant minutia that makes discussions like this impossible for those new to shooting so hard to follow.

          Sometimes we (and I include myself in this) confuse the issue by making one of two fundamental communication mistakes. We either:

          (1) Over complicate what should be simple explanations or
          (2) Oversimplify explanations by hitting the high spots to get the thought-juices flowing.

          I did the latter. In an effort to be brief and paint a picture that made sense, I tried to hit the high spots of what mattered to the question.

          If you want to discuss the physics of this in detail in another venue, I can provide a link to my contact page and we can bat it around that way.

          Unless and until then, I think the original asker of the question may now well be thoroughly confused by our helpful input. A saying about “good intentions” comes to mind …

        • “I’m not reading a long post…”

          Well at least we agree on one thing.

    • JR has the right idea.

      If a bullet fragments in bare gel, what is it going to do when it hits chest bone?

      Fragment would probably be a good guess.

      You want a round to get deep inside the chest cavity and make it to vital areas.

      Not bust up and end up in the chest muscles, or chest fat depending upon who you’re shooting.

  5. STB410, can I ask why you didn’t finished testing on Hornady Custom 147gr for only one round over penetrating 3/4 of an inch? But, kept testing other rounds with multiple bullets that under penetrated and broke apart?

    I would tend to lean more towards continuing to test a bullet that over penetrated slightly than the other way around.

    Something to that I’m missing? Just curious.

    • A couple of things on that… first, the Custom was “okay”, but nothing special. I’d already tested the Critical Defense and found it to be spectacular, so when the Custom came out kind of blah, I didn’t bother to go any further. The 147gr Custom was one of the first tests I did in the Ammo Quest 9mm series; I did a bunch of Hornady rounds in quick succession and I was blown away by how much better the Critical Defense was, as compared to any other Hornady offering.

      Second, but connected, was the notion that (especially in the early days of the Ammo Quest) my priority wasn’t necessarily on performing the most comprehensive test of that particular ammo, it was on finding the best-performing rounds. As soon as I saw overpenetration, I knew that round wasn’t going to make it to the top, so … I lost interest in it. I know (generally) how XTPs perform, and they typically penetrate as far or further in denim, so if it’s already overpenetrating in the bare gel, I was pretty sure the denim test would be a waste of time, based on my existing experience with XTPs.

      So, on to the DoubleTap — why did it get the full treatment? Just because I was more curious about it. I was interested in seeing what would happen with the claimed hyper velocity. Being a claimed 1395 fps from a 4″ barrel (not that I was using a 4″ barrel, but you see where I’m headed) I was just more interested in exploring it from both angles and seeing what it would do. Sure, I knew it was ruled out of contention after the first test. But for curiousity’s sake, I ran the second test just to see what it would do. And I’m kind of glad I did, I was really surprised that a round that basically disintegrated in the bare gel would hold together completely through the denim. Like I said, I am not sure I can explain WHY that happened, but it was interesting to see it happen in any case.

      Hope that all makes sense…

  6. Well with them splitting apart it would make getting them out by surgery a very hard job. However he is correct that they just didn’t do a good enough job to trust my life with them. Just my 2 cents worth.

  7. It seems like you don’t test denim over very minor things in the bare gelatin sometimes yet other times you go with the denim.

    • True, but see my reasons in the post above. The bare gel is the easier test to pass; heck, some people don’t even bother to test bare at all (which is a mistake, I think). If a bullet overpenetrates in bare gel, it is almost certainly going to overpenetrate further in denim. So sometimes I make that judgement call in the field, as to whether I should waste one of my $40 blocks of gel testing a round that’s already failed through the bare gel, or whether I should use that block testing a round that still has a chance of performing well.

      Sometimes, for curiousity’s sake or for the purpose of completeness, I’ll go ahead and run the round through the denim. But sometimes (and most especially for a known quantity like the XTP), I won’t bother. But recently, I’m tending more and more to just run both tests anyway.

  8. One can’t help but wonder, what happens with these if you put them in a pistol carbine where they go even faster. I kinda like the fragmentation actually.

    • Yeah, I do wish I had a Kel-Tec or something like that, to do exactly that test, just for grins.

      As for fragmentation — I don’t know if I effectively explained the difference between fragmentation, and disintegration. The 5.56 is a great example of fragmentation — it doesn’t “explode”, obviously, but the results look like it did — it sends shrapnel in all directions, and that helps exaggerate the wound channel. When a 5.56 round like M193 hits flesh, it yaws sideways, and the additional stress breaks the bullet apart and it fragments into a hundred pieces. Now, this happens early on, when the temporary stretch cavity is causing great stress on the flesh, so having a hundred shards of shrapnel flung outward violently causes the shrapnel to shred that stretched flesh, which greatly multiplies the amount of damage done. If you think about stretching a rubber band tightly, and then you just barely nick the edge of the stretched rubber band with a knife, it causes the whole band to tear in half. When the tissue is stretched tight, just a little cut or nick from a fragment of shrapnel can cause the flesh to rip, and that greatly multiplies the damage.

      Thing is, you can see this effect in the permanent damage track. Look at my test of .223 Lehigh Controlled Chaos or Winchester PDX1 .223, and the damage cavity is just a continuous tunnel of complete devastation, 3.5″ to 4″ in diameter and continuing for around 7 to 10 inches. It’s overwhelming.

      But that’s not what these rounds did. They didn’t fragment and create new wound channels, they just … disintegrated. Whereas the fragmenting rifle rounds behave more like a grenade going off in the body, these acted more like a sugar cube being crushed. They didn’t create new wound channels, all the fragmentation was basically just left behind in the existing wound channel.

      A nightmare for a surgeon to have to clean out? Most definitely. But more effective in stopping an attacker? Not inherently. In the end, it doesn’t result in a bigger wound channel, it just results in the final bullet being smaller overall, so that when it finally reaches the vital organs, it does less damage to them than a bullet that stayed together would have done.

  9. Ok, it takes more energy to go deeper. A clogged HP is going to keep it’s small diameter, and it’s not going to use any energy to the mushrooming. Which is why an HP that doesn’t expand, will overpenetrate and be bad news. The HP that DOES expand, but underpenetrates in bare gel, is more likely to be a survivable, or even simply a flesh wound. In this case, an overpenetrating projectile is preferable, because while it is not meeting it’s full potential, it is still going deep enough to hit organs. Where an underpenetrating round might not go deep enough to do anything useful.

    Look at the minimum. 12 inches. Now, remember, you can stick your finger 4 inches into gel pretty easily. But you can’t do that to your skin, bone, muscle… And the deeper the hole goes, the more energy it takes to overcome friction and push through tissue. That bullet is losing energy to all of that, as well as losing energy to the physical transformation.

    An underpenetrating bullet is worse than overpenetrating, simply because the overpenetrating bullet will at least hit organs.

    I’d hate to magdump on somebody, only to have them get back up, angrier.

    • Yep.

      Only thing I’d say is — nothing is guaranteed, so when shopping for ammo, I want something that’s going to be able to perform in every case. What I would classify as an underpenetrating bullet (something like PDX1 in .380, that barely managed to go 8″) would be something I would never, ever carry for defensive purposes. But, in the right scenario (a shot to the throat, for example) it would still be devastatingly effective.

      Even so, that doesn’t make it a good overall choice. I want something that has the potential to be devastatingly effective in all scenarios — head shots, throat shots, chest shots, gut shots. I want something that can shoot through a direct hit to the sternum, in a standing face-to-face encounter, but I also want it to be able to shoot upwards through the belly and still penetrate all the way to and through the vitals, in case I’m trapped laying flat on the ground and the attacker is looming over me (maybe with an axe or a bat, who knows?)

      I want to know that if the attacker’s pointing a gun at me in a weaver stance, with his left arm completely blocking his chest, I want to know that my ammo has the capability to burst totally through that arm, still bust through the chest, and still be capable of delivering a fightstopping hit. Liberty or G2 RIP or DRT may make a splashy-looking gel block, but if they encounter an arm on their way to the target, they’re going to disintegrate in the arm, leaving very little fightstopping potential.

      An overpenetrating bullet may increase your legal liability and may increase the potential of danger to property or even people beyond the target, and that’s all bad, but at least an overpenetrator will always have the ability to do some damage regardless of the angle or intervening arms. An underpenetrator may just fail to stop the fight, even with perfect shot placement.

      So for those reasons, if I HAD to choose between an overpenetrator and an underpenetrator, I’d choose the overpenetrator every time. Fortunately, we DON’T have to make that choice — there are enough solidly-performing, properly-expanding, deep-but-not-too-deep-penetrating bullets out there, that we can choose one that will have the best chance of performing properly in any given scenario. Obviously there will be exceptions, obviously there can be an unexpected failure and whatnot, obviously any bullet fired through a particularly thin area (like through a hand) is going to overpenetrate… you can’t control every possible variable, but what you CAN do is do the most you can to put the odds in your favor of having the most favorable outcome.

      And that’s my goal, in the Ammo Quests, is to find what ammo will put those odds most in our favor.

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