Several years ago, when Glock was introducing the model 42/43, there was a regional LE supply house which set up a demo in our area. It was a combo event where the Glocks were showcased and also some new Speer bullets. The main thrust was to illuminate the differences between duty ammo and self-defense ammo, based on the difference in applications. I was lucky enough to be one of the few from my department to be present at the event. We got to shoot for an entire day using different guns and rounds. Full size and compact and subcompacts. Duty rounds and defense rounds. Shot through glass, drywall, wood, steel, etc. Shot into gelatin. Shot different calibers. It was a very, very informational event.
Duty guns (those in full dress uniform) typically have barrels around 4.5" or greater. And duty applications have some specific needs (such as shooting through laminated glass in cars, etc). And so, the duty ammo needs to match the application. The rounds developed for these uses take into account the bullet weight, bullet design, barriers potentially present and barrel length.
Self-defense guns, especially those for concealed carry, have shorter barrels (around 3.5" or less) and also have fewer barriers to be concerned with. Typically the only barrier to overcome is clothing (seasonally changing). And so, the bullet weight, design and velocity has to be tailored to the unique differences.
Ammo manufacturers have come a long way in this regard. One such example is Hornady. They have Critical Duty (for LEO full size weapons) and Critical Defense (for short barrels). The two different ammos will work OK in either application, but they are optimized for specific applications. You can use Critical Duty in a Glk 26, but it won't be optimized for that application; it would not reach max velocity and it would have excessive muzzle flash because the powder charge would continue to burn past the end of barrel. And vice-versa; Critical Defense won't be optimized for a Glk 17 because it would complete it's max pressure well before the bullet reached barrel tip. Yes - these rounds will function in either application, but they are OPTIMIZED for specific applications.
The goal is to get the right amount of bullet penetration and expansion for the majority of expected instances of use. An incredible amount of engineering and testing goes into a properly designed round. The goal is to maximize expansion and penetration. Velocity is an important component, but it's only one of several characteristics to consider. And velocity is a function of bullet weight, propellant burn rate, barrel length, etc.
I emailed the following companies and asked specifically about the following; what ammo do they recommend for a short barrel, self-defense application? My parameters were about a Glock 26/43 (9mm with short barrel); however this would apply to other brands of weapons with similar characteristics. I specifically stated that I was concerned about excess muzzle flash, proper velocity for barrel length, proper expansion, etc. Note that if you change caliber or barrel length, the recommended grain weight will change, so always check the ammo manufacturer website for specifics.
Here are their direct answers ... for short barrel 9mm use:
Federal: Personal Defense HST 147gr JPH
Winchester: Defender product line in either 124gr or 147gr
Hornady: Critical Defense 115gr FTX ; Critical Defense Lite 100gr FTX (for lower recoil, typically geared towards women)
Remington: "UMC ammo." (a poor response IMO, because they did not offer any particular product details). UMC is a brand line, not a product specific offering for the parameters I asked about.
While I have a LOT of different guns, I typically only carry a Glk 26 now that I'm retired. Federal and Horady are the two which I'm most likely to use.
If you are interested in some other brands (Speet, CorBon, etc) then I recommend you directly contact them and ask about the specific parameters for your application.
