Ammo Selection



Over at, James Rummel posed a question: Glaser Safety Slugs: Are They Worth It?. After responding at length via comments, I realized that the debate was worth a post.

The conversation started with the topic of using shotshells for defense, and a commenter brought up Glaser Safety Slugs.  James described Glasers, and goes on to say that he doesn’t believe they are effective.  His reasoning was that there are 3 factors that make bullets effective in stopping fights:

1) “Shooting a violent criminal may well cause them to break off their attack due to psychological reasons.  (“Holy crap, I’ve been shot!”)”

2) “Blood loss will eventually cause even the most hardened, physically fit, and pain-inured criminal to pass out.  In fact, this is the only reliable mechanism for forcing someone to break off a violent attack.”

3) “The third mechanism for stopping an attack is what is usually referred to as “crush damage“, which is the tissue directly destroyed by having the bullet run into it.”

I do not believe that those are the only 3 factors that determine a bullets effectiveness, nor do I believe that those are the most important factors.  One can take a long time to bleed to death, after all, and during that time a perp can be pulling a trigger or swinging a knife.

Ammo effectiveness is a hard-to-define thing.  Many studies have been done, and the conclusions are argued about.  Much like the “1911 sucks vs. 1911 is the only worthwhile gun to carry” argument, there are multiple factions in the debate on stopping power (“light&fast vs. slow&heavy”) and some of them do not want to let go of their beliefs.    My response to James, via comments:

There are many factors that determine the performance of a bullet. While blood loss and crush cavities influence ammunition effectiveness, there is a factor which you did not address: energy transfer.

A speeding bullet carries energy. When it hits something, it begins to transfer that energy to whatever it hit. And that’s when it gets tricky. You need adequate energy from your ammunition, sure, but you also need an efficient way to transfer that energy to a target. (Analogy: the most powerful engine in the world is useless if you connect it to a crappy transmission.)

Given the same bullet diameter, heavier projectiles penetrate deeper, because of greater inertia. A bullet that is moving through a block of gelatin (for example) still has energy that it has not transmitted to its target. Deeper penetration damages more tissue and thus causes more bleeding, without a doubt. But deeper penetration translates into a SLOW transfer of the bullet’s energy to the target. The complaints about the 5.56mm SS109 projectile’s stopping power (despite 1300 ft/lb of energy)are mainly due to its tendency to overpenetrate and exit its target without transferring its energy to the target. The target can keep fighting because it did not receive a sufficient shock to its neurological system to make it stop functioning.

To cause neurological shock (or hydrostatic shock as some call it), you need to deliver a massive amount of energy to a target in an instant. The same amount of energy (or even a much greater amount of energy) delivered over a longer period of time will not cause shock.

Hollowpoints attempt to transfer energy to the target faster by increasing their frontal area, increasing the rate of energy transfer and causing more shock as well as greater tissue damage.

Glaser Safety Slugs (many small light projectiles travelling at higher velocity) were designed to dump all of a projectile’s energy into a target as fast as possible, thus causing maximum shock to the target’s nervous system. Against an unarmored, lightly-clothed target they are effective.

The problem is that they won’t penetrate body armor or even heavy clothing like denim jackets. That’s an advantage if you don’t want to shoot through an apartment wall and injure a neighbor, but it is a disadvantage if you might be trying to stop an attack by someone with heavy clothing on.

Glasers are the lightest & fastest extreme on the light&fast vs. slow&heavy spectrum.

WilliamTheCoroner chimed in that FMJ ammo works fine, in his opinion (an opinion that I have disagreed with him on, LOL).  He also mentioned that Glasers do a lot of damage if they penetrate the target’s clothing.

I know that Evan Marshall and Ed Sanow compiled a lot of ammo performance stats in their books Handgun Stopping Power and Street Stoppers.  And they also reprinted the results of ammo testing by various agencies.  I refreshed my memory and added another response to James:

OK, here’s what I found. In Street Stoppers by Evan Marshall & Ed Sanow, they reprint the results of 5 different studies of handgun ammunition effectiveness:

The infamous Strasbourg Goat Tests
The Navy-Crane 9mm ammo test
The Police Marksman/Fairburn study (not Fairbairn)
The Royal Canadian Mounted Police test
The Secret Service test

The Navy-Crane test involved 10 types of commercial 9mm hollowpoint ammunition, and was used to determine the issue ammunition for the Naval Investigative Service in 1991. Functional reliability was 50% of the criteria (not totally objective, some subjective opinions were counted); penetration into bare gelatin and bare gelatin after going through glass was 25%, expansion in gelatin and group size at 50yds were worth 10% each and retained bullet weight was 5%. (Note, I do not recommend these exact percentages for selecting personal defense ammo). The conclusion was to select a Federal 147gr JHP. And it was a bad decision, due to unrealistic weighting and the inclusion of subjective data in the weighting. When the data is analyzed with more realistic weighting and no subjective observations, 115gr and 124gr JHP ammo performs best.

Police Marksman magazine published a 4-year study of ammo performance in 1993. It wasn’t a test; they solicited information on shooting incidents from police officers. While the man who conducted and tabulated the survey was a proponent of slow heavy expanding bullets, his study showed them to be inferior to lighter faster expanding bullets.

The 1994 RCMP tests compared the performance of 9mm and .40S&W ammo (in 4″ pistols and a 9mm HK MP5 with 9″ barrel) to the then-issue .38+P 158gr LSWCHP (lead semi-wadcutter hollowpoint, fired from a 5″ barrel) in gelatin, in clothed gelatin, and in gelatin with a section of pig rib embedded in it. The tests were conducted at 3 meters and 50 meters. The researchers were looking at total penetration, recovered bullet diameter, weight retention and % of retained weight. Penetration of less than 12″ or more than 18″ into bare gelatin disqualified a round, as did expanded diameters less than the issue .38 round. While the researchers did not recommend a specific replacement ammo, the results were interesting; the issue .38 ammo overpenetrated bare & clothed gelatin when fired from a 2″ barrel. Light 9mm rounds that tend to fragment (and have excellent real-world performance) were deemed unacceptable based upon the test criteria.

The Secret Service (which does not share much information) tested .38 ammo in 1972 and did some testing of 9mm ammo in 1987. Bear in mind that the Secret Service and the FBI have different roles and are likely to have to use their weapons in different environments. The FBI overreacted to the Miami Shootout and overemphasized penetration in setting its criteria for ammunition testing. Conclusions: hollowpoints are most effective, FMJ were least effective, and JSP fell in between the two.

The Strasbourg Goat Tests (which some claim were a hoax) took place in 1991, and used goats (with bone composition similar to humans, unlike pigs which have more fat and less calcium in their bones causing them to affect bullets differently) wired for electroencephelography (EEG) and arterial transducers to record the animals’ responses before during and after bullet impact. The point of aim was the goats’ chest cavity, with the intent of hitting a lung. The goats were not anesthetized.

They tested .380, .38+p, 9mm, .357mag, .40s&w, 10mm and .45acp; ammunition designs included Black Talon, Hydra-Shok, Glaser, MagSafe, Silvertip, XTP, Nyclad and standard jacketed & unjacketed hollowpoints.

The conclusions:
1) prefragmented/frangible rounds worked best for an unobstructed lung shot.
2) rounds that expand and then fragment incapacitated faster than rounds that only expanded.
3) hollowpoints that expand immediately incapacitated faster than bullets designed for controlled/delayed expansion.
4) more rapid rates of bullet expansion caused more organ damage.
5) higher impact velocity that caused more rapid expansion led to the highest blood-pressure spikes and greatest blood loss.
6) non-expanding bullet designs took the longest to incapacitate, if they were even able to incapacitate.
7) bullets that struck a rib took longer to incapacitate (usually twice as long) than bullets that entered cleanly. Round-nose bullets and hollowpoints with small openings performed the worst after hitting bone; wide hollowpoints were least affected by bone impacts

Regarding Glaser/MagSafe ammo, they were part of the Strasbourg tests. The point of the tests was to see what ammo would incapacitate a target fastest.

For the calibers that were tested:
.380 – MagSafe and Glaser Blue were the fastest and second-fastest incapacitators
.38SPL (4″ BBL) – Glaser Blue was #1 and MagSafe was #2.
.45acp – MagSafe and Glaser Blue were #1 and #2
.40S&W – MagSafe and Glaser Blue were #1 and #2
10mm – MagSafe was #1 and Glaser Blue was #3
.357mag – QuickShok (prefragmented) was #1, MagSafe was #2 and Glaser Blue was #3
9mm – MagSafe was #1, QuickShok was #2, Glaser Blue was #3

Given the test methodology (straight-in, chest/lung shot placement, no clothing), the results are compelling.

I can’t be too much more detailed, or I am skirting copyright issues.  You really should read the book for yourselves.

I want to be clear: there is a somewhat narrow window of engagements where Glasers are the best choice for defense.  When there is no chance the target will have on thick clothing, and no chance they will be behind any sort of barrier (even if it isn’t “cover”), Glasers are a viable choice.  When minimizing penetration/ricochets is a strong incentive, such as in an apartment, Glasers also make sense.  But the user needs to truly understand the ammo’s limitations.  The fact that the Glasers are much lighter than traditional bullets means that they won’t be hitting targets where the gun’s sights are aiming (if the gun is sighted in with traditional ammo).  So switching back & forth between Glasers and regular ammo isn’t risk-free.

Glaser Blue

Glaser Blue

The problem is that as law-abiding civilians, we rarely get to dictate the time and the conditions where we will be using our guns in a defensive manner.  We might have to shoot through a door, a car window, or at a criminal with heavy clothing, all of which will reduce or even eliminate the power of a Glaser bullet, while having little or minimal effect on a traditional bullet design.  Since we cannot be sure that we will be engaging a target that falls within the Glaser’s window of effectiveness, Glasers are not what I would choose for everyday carry.  A light&fast-for-caliber, rapid-expanding hollowpoint is what I choose for most defensive scenarios.



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3 Responses to “Ammo Selection”

  1. Thank you kindly for the link, G-N!

  2. […] GunNutmegger weighs in with some hard data. […]

  3. kws says:

    Why are denim jackets often used as examples of “heavy clothing”? I’ve never seen anyone wear one or found one in a store in _years_. Leather jackets, yes. The Carhartt style duck jackets, yes. Denim, no.

    Which sorta torques me off since I used to wear them when I was a kid and can’t find one now. 🙁

    • Gunnutmegger says:

      I think they are used because denim is commonly available in some form, and is a relatively durable fabric. I think I read that it tends to plug the cavities of hollowpoints, so it’s a good test for real-world ammo performance.