# Why do police use 9mm firearms? **URL:** \ **Category:** Factual Questions\ **Created:** [December 6, 2014, 2:58am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469 "2014-12-06T02:58:37Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Ambivalid](https://avatars.discourse-cdn.com/v4/letter/a/a5b964/32.png) [@Ambivalid](https://boards.straightdope.com/u/Ambivalid)\ **Post date:** [December 6, 2014, 2:58am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/1 "2014-12-06T02:58:37Z")
With all the recent news and discussion of law enforcement and use (and misuse) of lethal force, a particular question came to mind re the selection of 9mm firearms as the standard gun issued to policemen. Given that police are trained to use deadly force only as a last resort, it therefore makes sense that they are trained that when it _does_ become necessary to use that gun, to shoot to kill. To neutralize the threat. With all of this being true (and please correct me if not), why is such a relatively small caliber gun chosen to carry out these ‘shoot-to-kill’ tasks? Are there other considerations taken into account when selecting the weapon? Based on pure “stoppability”, it would seem like a .45 would be a better fit than a .9. ---
**Author:** ![kopek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kopek/32/337_2.png) [@kopek](https://boards.straightdope.com/u/kopek)\ **Post date:** [December 6, 2014, 3:28am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/2 "2014-12-06T03:28:23Z")
It’s basically the automatic version of the standard .38 special they used forever in the revolver years. It gives a pretty good hit, it’s fairly easy to handle and it doesn’t shoot through too many people or things. Also give higher capacity clips than most other calibers. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [December 6, 2014, 3:31am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/3 "2014-12-06T03:31:15Z")
Consider that prior to WWII, many European police used .32 ACP pistols; and a .32 was popular with criminals there and in the U.S. Nine millimeter is perfectly capable of taking down a criminal. Also, American police forces have in general not used .45 ACP. Before the proliferation of 9 mm, most cops were armed with .38 Special revolvers. The 9 mm has a big advantage over the .38 Special and the Colt 1911 .45 ACP models: They tend to have large magazines. In the 1987 shootout in North Hollywood, many of the cops were armed with their .38 revolvers. (Some had 9 mm.) The criminals were armed with illegally-modified (not to mention illegally-possessed) machine guns. Police had to borrow AR-15s from B& B Sales, which was across the way. It seems that that was when police forces they needed the ability to put out a greater volume of lead. Fifteen-round magazines in 9 mm pistols fit the bill. ---
**Author:** ![Patch](https://avatars.discourse-cdn.com/v4/letter/p/a183cd/32.png) [@Patch](https://boards.straightdope.com/u/Patch)\ **Post date:** [December 6, 2014, 3:32am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/4 "2014-12-06T03:32:55Z")
> [@Ambivalid](#): > > With all the recent news and discussion of law enforcement and use (and misuse) of lethal force, a particular question came to mind re the selection of 9mm firearms as the standard gun issued to policemen. Given that police are trained to use deadly force only as a last resort, it therefore makes sense that they are trained that when it _does_ become necessary to use that gun, to shoot to kill. To neutralize the threat. > > With all of this being true (and please correct me if not), why is such a relatively small caliber gun chosen to carry out these ‘shoot-to-kill’ tasks? Are there other considerations taken into account when selecting the weapon? Based on pure “stoppability”, it would seem like a .45 would be a better fit than a .9. 9mm is an effective caliber, you can carry more ammunition in a magazine, recoil is lower so the firearm is easier to control, grips are smaller so they’re easier to manage for a wider range of people, and ammunition is cheaper so it’s less expensive to train. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [December 6, 2014, 3:38am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/5 "2014-12-06T03:38:40Z")
> [@Patch](#): > > you can carry more ammunition in a magazine… grips are smaller so they’re easier to manage for a wider range of people I have a Beretta 92FS and a Colt 1991-A1 and a Colt Government Model 1911. The grip on the Beretta is considerably beefier than on the Colts. I’ve handled a Browning Hi-Power. I think the grips on high-capacity 9 mm pistols are bigger than on a single-stack .45 pistol. The P.08 I used to have and the P.38, both of which have single-stack magazines, are closer to the Colt. (The P.38’s grip is closer to the 1911-A1 in size.) ---
**Author:** ![obbn](https://avatars.discourse-cdn.com/v4/letter/o/d6d6ee/32.png) [@obbn](https://boards.straightdope.com/u/obbn)\ **Post date:** [December 6, 2014, 3:48am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/6 "2014-12-06T03:48:54Z")
Around here most of the local departments have changed from 9mm to the .40 caliber. The .40 is bigger bang without much sacrifice in number of rounds carried. The 9mm however is a fine self defense round, it’s the one I have chosen for concealed carry. I thought about a .45 when I chose my weapon but the higher capacity magazine and lower recoil won out. ---
**Author:** ![thelurkinghorror](https://avatars.discourse-cdn.com/v4/letter/t/7c8e57/32.png) [@thelurkinghorror](https://boards.straightdope.com/u/thelurkinghorror)\ **Post date:** [December 6, 2014, 4:02am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/7 "2014-12-06T04:02:46Z")
Yes, many use .40. That is basically a shortened 10mm, and there are jokes that 10mm was too much for the FBI. Police adoption of 9mm was partially fueled by the [new, reliable semiautos](http://en.wikipedia.org/wiki/Wonder_Nine) which happened to come in 9mm in the 70s. Police and militaries like standardizing to one platform so it could reach critical mass when you adopt it because the next town over has. If a suspect is armored enough that 9mm is ineffective, then .45 is unlikely to be effective. You’d need a rifle or shotgun at that point. ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [December 6, 2014, 4:14am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/8 "2014-12-06T04:14:00Z")
> [@Johnny\_L.A](#): > > I have a Beretta 92FS and a Colt 1991-A1 and a Colt Government Model 1911. The grip on the Beretta is considerably beefier than on the Colts. I’ve handled a Browning Hi-Power. I think the grips on high-capacity 9 mm pistols are bigger than on a single-stack .45 pistol. The P.08 I used to have and the P.38, both of which have single-stack magazines, are closer to the Colt. (The P.38’s grip is closer to the 1911-A1 in size.) I don’t have a 1911, but o have fired them. The grip on my XD-9 fits my small hand better. The difference is not how thick the grip is but how (what the right word?) wide? Long? It is. If you were to measure from the front of the grip under the trigger guard to the rear of the grip under hammer the 1911 feels much longer to me. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [December 6, 2014, 4:18am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/9 "2014-12-06T04:18:27Z")
> [@Patch](#): > > 9mm is an effective caliber, you can carry more ammunition in a magazine, recoil is lower so the firearm is easier to control, grips are smaller so they’re easier to manage for a wider range of people, and ammunition is cheaper so it’s less expensive to train. As someone who has a minimal amount of shooting experience, and I know police have a ton more than I do, that’s what I was thinking. A .45 is a lot to handle, and probably a lot more to handle in a high stress environment. I own a .45 and (keeping in mind that I have very little range time with it) would love to trade it in for a 9mm. I’ve used both and have much better control with a 9mm. The .45 throws my arm all over the place while the 9mm, after a bit of practice almost feels like a .22, like a plinker. I can shoot one round after another and keep hitting the target while with the .45 I had to stop in between each shot to re-aim. It’s funny, on gun boards you’ll hear things like ‘stopping power’ (don’t get a XX caliber, it doesn’t have enough stopping power) and my thought was always ‘um, if you get shot, it’s not like the movies, you’re going to go down’. However, when I took my gun safety class to get my CCW, the guy mentioned that with a small enough caliber (such as a .22), some people really won’t stop. If someone is coming at you or robbing you, especially if they’re on crack or drunk or on PCP and you hit them with a plinker, now they’re going to be mad AND have a gun. That’s where they theory of unloading the entire clip (and putting another one in and unloading that one) comes into play. If there’s a threat you keep shooting until it’s gone, you don’t just put one in their leg and assume the situation is under control. Having said that, I don’t know how much more damage a .45 does over a 9mm, but it is easier to handle. Also, with smaller bullets you can fit more in the magazine and the grip is going to be smaller making it easier for some people to hold. FTR, I could be wrong on all this, it’s just my very uneducated WAG about it. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [December 6, 2014, 4:22am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/10 "2014-12-06T04:22:00Z")
> [@Rick](#): > > I don’t have a 1911, but o have fired them. The grip on my XD-9 fits my small hand better. The difference is not how thick the grip is but how (what the right word?) wide? Long? It is. > If you were to measure from the front of the grip under the trigger guard to the rear of the grip under hammer the 1911 feels much longer to me. Funny you said that, I have a friend that’s a shooting instructor take me out to his personal range. It was one of the first times I went shooting and the first thing he did was bring out about 5 guns and asked me which one I wanted to shoot. I sort of shrugged my shoulders and commented that it didn’t matter to me. He told me to pick up each one and see how they feel. One of them was just like that, too ‘long’, it couldn’t wrap my hand around it. It was almost like my middle knuckle was on the side inside of the end of it, I couldn’t make a ‘fist’ around it. It was very uncomfortable. It was really easy to say ‘not that one for sure, it doesn’t feel right’. ---
**Author:** ![rsa](https://avatars.discourse-cdn.com/v4/letter/r/839c29/32.png) [@rsa](https://boards.straightdope.com/u/rsa)\ **Post date:** [December 6, 2014, 4:41am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/11 "2014-12-06T04:41:28Z")
IIRC, Austria did extensive testing of handguns in the 80’s to select a new sidearm for their military. The new at that time Glock was selected for its reliability, multiple passive safety features and the general 9mm advantages noted above. It was soon after this that I started to notice that U.S. police departments were starting to use Glocks for the same reasons that it was picked by the Austrians. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [December 6, 2014, 5:12am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/12 "2014-12-06T05:12:53Z")
> [@rsa](#): > > IIRC, Austria did extensive testing of handguns in the 80’s to select a new sidearm for their military. The new at that time Glock was selected for its reliability, multiple passive safety features and the general 9mm advantages noted above. It was soon after this that I started to notice that U.S. police departments were starting to use Glocks for the same reasons that it was picked by the Austrians. Glock makes all different sized pistols. For example, the G21 is a .45 caliber that has (to the best of my knowledge) the same 3 safety features as the G19. In fact, I think all their guns do, so while the safety features may have been a reason to use Glocks, it’s not a reason to chose a certain sized bullet. It should be noted that sometimes Glocks can be controversial because they have no safety switch. They’re always ‘hot’ and they’ll always go off if you pull the trigger (assuming one in the chamber). The safety features prevent them from going of if you don’t pull the trigger. That is, it’s very unlikely that the trigger will get snagged on something like a piece of clothing or an ill fitted holster, it won’t go off if you drop it or fumble with it for some reason etc, but they do bother a lot of people because of the lack of an actual, mechanical, safety switch. ---
**Author:** ![enipla](https://avatars.discourse-cdn.com/v4/letter/e/54ee81/32.png) [@enipla](https://boards.straightdope.com/u/enipla)\ **Post date:** [December 6, 2014, 5:23am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/13 "2014-12-06T05:23:45Z")
Maybe a side note… But didn’t the US national park rangers fight for and adopt the .357 revolver about 5 years ago? My Google fu is lacking. I think they did. I wonder if it replaced a .38 and if they ever carried semi-autos. I could see some reasons for this, and some not. Out in dirt and grime, a revolver may be a better choice. And the .357 packs a lot more than a .38. And the .357 is much better if big game needs to be put down. But, I know these guys must be carrying rifles in the truck. And at least for the Colorado Division of Wildlife, I’ve seen it. It sort of surprises me. I would think that most Park Rangers respond to rowdy campsites where firepower would be a better choice. When the rifle needs to be pulled out for big game, they have it. It’s just kind of interesting to me. I shoot both the .357 and the 1911 .45. ---
**Author:** ![obbn](https://avatars.discourse-cdn.com/v4/letter/o/d6d6ee/32.png) [@obbn](https://boards.straightdope.com/u/obbn)\ **Post date:** [December 6, 2014, 6:22am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/14 "2014-12-06T06:22:30Z")
> [@Joey\_P](#): > > Glock makes all different sized pistols. For example, the G21 is a .45 caliber that has (to the best of my knowledge) the same 3 safety features as the G19. In fact, I think all their guns do, so while the safety features may have been a reason to use Glocks, it’s not a reason to chose a certain sized bullet. > It should be noted that sometimes Glocks can be controversial because they have no safety switch. They’re always ‘hot’ and they’ll always go off if you pull the trigger (assuming one in the chamber). The safety features prevent them from going of if you don’t pull the trigger. That is, it’s very unlikely that the trigger will get snagged on something like a piece of clothing or an ill fitted holster, it won’t go off if you drop it or fumble with it for some reason etc, but they do bother a lot of people because of the lack of an actual, mechanical, safety switch. This is true of the Glock series of pistols and quite a few others. I carry a Springfield XDS 9mm that does not have a traditional safety. However, to fire the weapon you must be holding it with a shooting grip, your hand must be wrapped around the grip, as it has a lever on the grip that must be pressed. It also has a trigger safety, that is a trigger on a trigger that has to be depressed before it will fire (meaning a trigger snag most likely will not result in a discharge as both triggers must be squeezed. ). The combination of the two make an accidental discharge highly unlikely. If the trigger is pulled and your hand isn’t wrapped around the grip, no bang. As far as dropping the weapon, all pistols that are of new manufacture come with drop safeties that prevent the firearm from discharging in the event it is dropped. Even though there are quite a few handguns that come without traditional mechanical safeties, the likelihood of an accidental discharge is extreme remote if the user is practicing safe gun handling. ---
**Author:** ![thelurkinghorror](https://avatars.discourse-cdn.com/v4/letter/t/7c8e57/32.png) [@thelurkinghorror](https://boards.straightdope.com/u/thelurkinghorror)\ **Post date:** [December 6, 2014, 7:07am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/15 "2014-12-06T07:07:38Z")
> [@enipla](#): > > Maybe a side note… But didn’t the US national park rangers fight for and adopt the .357 revolver about 5 years ago? My Google fu is lacking. > > I think they did. I wonder if it replaced a .38 and if they ever carried semi-autos. > > I could see some reasons for this, and some not. > > Out in dirt and grime, a revolver may be a better choice. And the .357 packs a lot more than a .38. And the .357 is much better if big game needs to be put down. But, I know these guys must be carrying rifles in the truck. And at least for the Colorado Division of Wildlife, I’ve seen it. > > It sort of surprises me. I would think that most Park Rangers respond to rowdy campsites where firepower would be a better choice. When the rifle needs to be pulled out for big game, they have it. > > It’s just kind of interesting to me. I shoot both the .357 and the 1911 .45. No idea. And .357 is better than .38, even .38 +P, if you have a chance of finding bears\*. But there is almost no reason to prefer .38, because .357 can shoot both. The only reason I don’t is because the .38 I have was free! There are slight increased size/weight considerations and barrel length. But 5 years is an extremely delayed adoption considering, as above. .38 became “obsolete” decades ago. But then I’m from a NPS family and I understand. And for rangers\*, the capacity probably matters less when the main concern is 500 pounds. \*Just learned: Denmark’s Slædepatruljen Sirius is one of the few military units to issue 10mm. Because they operate in Greenland and because [del]godless killing machines[/del] _polar bears_. \*\*I used to be an ((sub)urban park, not federal) ranger. All I got issued was a fully automatic walkie talkie. ---
**Author:** ![Sage\_Rat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sage_rat/32/399_2.png) [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)\ **Post date:** [December 6, 2014, 7:10am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/16 "2014-12-06T07:10:46Z")
Based on some research I did before, it seemed like the best “stopping power” of common pistol rounds was the .40 S&W, based on ballistic tests against gelatin. The .45 ends up losing out because, even though it’s larger, it’s going slower and ends up not having the same amount of force. In real-world life, the 9mm is actually the round with the highest kill rate, per shot taken. However, if you ignore the 9mm, the gelatin test results for lethality match the real world statistics. So it’s believed that the fact that police carry 9mms and are actually trained in how to aim and kill influences the real world results, beyond the effectiveness of the round. But certainly, any of the three is deadly enough that you don’t want to get hit with it. ---
**Author:** ![Bone](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bone/32/407_2.png) [@Bone](https://boards.straightdope.com/u/Bone)\ **Post date:** [December 6, 2014, 7:39am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/17 "2014-12-06T07:39:18Z")
On[page 20 of this LAPD 2011 Use of Force report](http://www.lapdonline.org/assets/pdf/2010YearEndReport.pdf), it shows that of 74 incidents, the police firearm in the largest category of use was the Glock .40. This was used in 28 of the 74 incidents. I’m sure this varies by department but I’m not sure that 9mm is the outright favorite for police use. That being said, the reasons why I chose 9mm for my personal use is partly related to it’s popularity among police. If you are ever forced to use your weapon, saying you use the exact model and type that your local police use deflects any criticism of the choice of weapon. That and rounds are cheaper, lighter, and generally have greater magazine capacity. All of these things makes practice easier and more enjoyable. More practice is better. ---
**Author:** ![Patch](https://avatars.discourse-cdn.com/v4/letter/p/a183cd/32.png) [@Patch](https://boards.straightdope.com/u/Patch)\ **Post date:** [December 6, 2014, 8:12am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/18 "2014-12-06T08:12:47Z")
> [@Bone](#): > > On[page 20 of this LAPD 2011 Use of Force report](http://www.lapdonline.org/assets/pdf/2010YearEndReport.pdf), it shows that of 74 incidents, the police firearm in the largest category of use was the Glock .40. This was used in 28 of the 74 incidents. I’m sure this varies by department but I’m not sure that 9mm is the outright favorite for police use. The .40 reportedly has better performance against barriers, making it more useful for law enforcement as they work around cars a lot. ---
**Author:** ![Patch](https://avatars.discourse-cdn.com/v4/letter/p/a183cd/32.png) [@Patch](https://boards.straightdope.com/u/Patch)\ **Post date:** [December 6, 2014, 8:15am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/19 "2014-12-06T08:15:29Z")
> [@Johnny\_L.A](#): > > I have a Beretta 92FS and a Colt 1991-A1 and a Colt Government Model 1911. The grip on the Beretta is considerably beefier than on the Colts. I’ve handled a Browning Hi-Power. I think the grips on high-capacity 9 mm pistols are bigger than on a single-stack .45 pistol. The P.08 I used to have and the P.38, both of which have single-stack magazines, are closer to the Colt. (The P.38’s grip is closer to the 1911-A1 in size.) I have a Sig P220 (single stack .45), P229 (double stack 9mm) and a Glock 17(double stack 9mm). I measured around the grips, and they’re all roughly the same. However, I do recall handling a Glock 20 (single stack .45) and I found the grip too big, so it looks like it’s going to vary with firearm. ---
**Author:** ![thelurkinghorror](https://avatars.discourse-cdn.com/v4/letter/t/7c8e57/32.png) [@thelurkinghorror](https://boards.straightdope.com/u/thelurkinghorror)\ **Post date:** [December 6, 2014, 8:30am UTC](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469/20 "2014-12-06T08:30:12Z")
> [@Patch](#): > > The .40 reportedly has better performance against barriers, making it more useful for law enforcement as they work around cars a lot. [Summary](http://www.theboxotruth.com/the-buick-o-truth-3-pistols-and-car-doors/). TL;DR: .40 might be slightly better, but a car door is no protection even for smaller rounds. If that’s the barrier you’re worried about, it probably doesn’t matter. [Next page](https://boards.straightdope.com/t/why-do-police-use-9mm-firearms/706469.md?page=2)