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The November issue of American Rifleman [print only] contains an interesting article about expanding bullets. Although the article is aimed at hunters, there’s some insight for those of us who skew towards defensive firearms. Author John Barsness does a great job of breaking down the factors that constitute “stopping power”—though that phrase is never mentioned . . .

As our better informed readers know (i.e. all of you), the only way to instantly stop a 150-200+ pound threat is to either disrupt the central nervous system (CNS), or cause a sudden drop in blood pressure, aka shock. To that end, I bet that most of us who live in states that abide by the Constitution generally use +P hollow points in our carry guns.

[Don’t worry, the article isn’t one of those “broccoli causes cancer and bacon cures it” exposés. It’s just that placement matters much more than bullet performance.]

The three +1 measurable metrics that define bullet performance are energy, penetration in a standard medium, and expansion and weight retention. There are two contradictory theories regarding energy, expansion, and penetration.

On the one hand, someone might say that a bullet that didn’t exit the target did not penetrate enough. On the other hand, some would say that a bullet that exited the target did not impart all of its energy. While the intelligent observer might fall into one camp or the other, the truly sharp will realize that neither tells the whole story.

First, expansion and weight retention . . .

In the article, the author relates how he shot a prairie dog with a 180 grain handload out of a .30-40 Krag. The exit wound was ¾ of an inch, indicating that even in an animal that small, the bullet had time to expand. According to the author most hunting bullets will have fully expanded by the time they penetrate their own length.

I don’t know how true that is for defensive handgun rounds, but it is interesting.  Furthermore, with very high velocity cartridges—think 5.56 and hotter—the goal is fragmentation rather than expansion and weight retention.

Although hunters typically only use these calibers on very small game, the US military seems to think it is suitable for use on people. Of course, neither people who shoot varmints nor the military are worried about damaging the meat.

Next up, energy . . .

Energy is easy enough to define; Newton did it for us four hundred years ago. But what does it mean in terms of stopping power? I honestly don’t know how energy affects performance. If a hot +P 9mm has roughly 450 foot-pounds of energy, what does it mean if the bullet did or did not exit the target? Assuming that the target stopped the bullet, then where did that 450 foot-pounds go and what did it do?

Most likely it just got converted into heat and then dissipated, which is how car brakes work. If someone could explain to me how dumping energy into the target disrupts the CNS or causes a loss of blood pressure I would appreciate it very much. The author and I agree on that point.

Saving the best for last, penetration . . .

Neither bad guys nor moose consist of a standard medium. They have bones of varying sizes and possibly clothing. Here again, placement is key; how far the bullet will penetrate depends on what it is penetrating.

The two elements of bullet design that affect penetration are weight retention, and expansion.  The author’s wife shot a moose that was quartering away with a 150 grain Nosler partition and it penetrated 30” of the chest cavity through mostly soft organs.  The same bullet had been stopped in less than 15” when fired at the shoulders of an elk, the difference being all the big muscles and bones in the way.

In the final anecdote of the article, a friend of the author shot a 100 lb deer with a 360 grain wildcat moving at 2700 fps. That’s over 5800 foot-pounds of energy. The bullet retained 90 percent of its weight, but expanded over twice its diameter—and did not exit the deer. The large frontal area was sufficient to slow it in the small target, a different bullet design probably would have gone through.

So what does it all mean? I’m more confused now than when I first read the article. I think I am sticking to my own theory: assuming that there is nothing important behind the target, two holes are better than one for reducing blood pressure.

Remember that little deer? The most important point in the whole article as far as defensive use of firearms is concerned: the deer was not even knocked down. It actually stumbled a few yards before it fell down and died.

Think about that. According to this author and others, after a hit to the chest cavity, it takes at least 10 seconds for blood pressure to drop enough for the target to stop moving. If a bad guy is coming at you with a weapon, especially a knife, those will be the longest 10 seconds of your life.

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  1. re-2 holes, I meant that I think an exit wound is better than not, ceteris parebus.

    In poking around the web researching this piece I found a number instructors promoting shooting the pelvis first, since there is a chance of hindering the mobility of the threat.

  2. Since we're talking about defense, and carry caliber. You should be more explicit about the value of shooting 2 9mms vs. 1 45. 2x the chance of a CNS hit. Also from a pressure drop consideration 1.5x the area and 2+x the wound length (circumference). I'm reminded of an incident about 20 years ago in which a Miami Beach Police office vs bad guy armed with Sig 226 and Glock 20 (10mm) respectively fired and hit all rounds fired into each other from 10'. Both lived. One of the 506E guys in Bastogne got hit center of mass by 9 8mm's and kept fighting, walked several miles and lived. People have instantly died from a .22 short in the membrane.

    Placement, placement, placement.

    As for hollow point performance, the German military and police believe that FMJ is a better defensive load since the exit wound doubles blood loss. The 125 gr. Federal .357 Magnum semi-JHP load was the police/DOJ gold standard for best 1 shop stop potential (~85%) for a generation. It has reliable expansion, also plenty of energy to push it through. HP may add a lot of stopping value, particularly for high energy +P+ 9mm from a full size barrel. I'd avoid it in favor of maximizing penetration for a .32. In a short barrel 9 it depends. Is it a belly gun? Do you expect to shoot through cover? Shoot through a vehicle?

    The one rule that applies to all situations is there's no replacement for placement, to that end carry more capacity at the expense of bullet diameter. The extra rounds also help if you miss which tends to happen more when the SHTF.

  3. I'm no ballistics expert, but my beliefs–The size of the entrance and exit wounds aren't as important as the amount of blood vessels compromised, and the likelihood of hitting a vital spot. Blood that can't get back to the heart is just as useless in supporting consciousness as blood that leaves the body entirely. FMJ rifle ammo may have enough velocity to damage at some distance from the actual track. Hollowpoints with enough penetration can create more internal wound surface area to bleed-both larger diameter and more irregular. Even without an exit wound, blood lost from the circulatory system is likely faster than a through-and-through with a FMJ, and the larger diameter is a bit more likely to connect with something immediately incapacitating.

    …and thinking about it at this level of detail feels creepy.

    Marshall's one shot stop statistics are not scientific. There are global-warming type issues with the raw data, and the definition itself is flawed as a real-world measure of the effectiveness of repeating handguns–shooter skill, shot placement and number of shots fired are not independent of ammo type.

  4. +1 to Sevesteen.

    A JHP will fragment causing more irregular damage, which makes it more likely to hit something that you may not with a FMJ. Also, as he says, the amount of blood leaving the body is almost irrelevant when compared to the amount of blood that can't make it back to the heart and from there back to support the body. FMJ rounds, however, do have the advantage of creating what was defined by Rabbi as a temporary wound cavity, which briefly increase the pressure on organs, blood vessels, and tissues, which can (but won't always) cause them to rupture. This is where the majority of the energy is lost from a FMJ round on its way through a target. A JHP, due to its fragmentation, will not provide that "bursting energy" as much.

    I'm not a ballistics expert, but this is more or less my understanding of how most energy is lost from these bullets: Fragmentation for the JHP and the temporary wound cavity for the FMJ. As most everyone has said though, placement is key.

    Oh, and the Wikipedia article on shock (better defined as circulatory shock) provides some excellent information. Essentially, there's not enough oxygenated blood getting to various parts of the body, so those parts shut down to try and preserve central function before that too is lost. Lose a lot of blood, and you won't walk away, even if the blood loss had nothing to do with your legs or brain directly (i.e. you chopped your hand off).

  5. Check out my assortment of 50 cal. ammo for my S&W 500’s (4, 8/38 and 10.5 inches) on Bob’s I want a S&W 500 story. They range from 300 grain hollow points to the T rex of all handgun bullets, the mighty 700 grain flathead. I don’t care where you place any of these bad boys cuz the perp will bleed out before you can dial 911. The 300 to 500 grain rounds are easy to shoot, the 600 is mighty powerful and the 700 grain is the sickest thing you can shoot out of a hand cannon (anyone who has shot this round will testify to that fact) and will truely amaze you.

  6. Location, Location, Location; Like in Real Estate and sales, it is all about location.
    Funny how shooting and business goes hand in hand, but after all shooting is a business, whether it is recreational, hunting or protective. We strive for a ‘clean hit’
    Vital debilitating hits are the key. Round size is not always the key, Penetration through and through clean is also a weak shot.

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