Why did every law enforcment switch to .40 from 9mm?

Actually a 9mm can hold more rounds. Originally they went to the 10mm, but it was to powerful for some shooters, so they loaded it down and called it a 40SW. Truth is all handguns are bad man stoppers. 6 out of 7 gun shot victims survive. So that being said, what ever caliber allows you to shoot accurately and carry the most ammo is actually the best choice. The difference between 9mm, 40SW, and 45ACP is not ever worth debating.

The problem with the 45ACP is that it the rounds are even larger, therefore it holds even less rounds than the 40SW. The 40SW seems to be the middle ground between the 9mm and 45ACP or at least that is the consensus. But again, the difference between any of the listed calibers is far to close to worry about. I would be more worried about placing the shot accurately than the caliber of the round. I assure you, the assailant won't complain. If you really want a man stopper, put down the handgun and pick up a rifle.

So there was a famous shoot-out in Miami where 8 FBI agents went against 2 bank robbers. 2 bank robbers were killed, but so were 3 FBI agents and 5 FBI agents were severely wounded. 2 agents had shotguns, 3 had 9mm handguns, 1 agent had a 357 handgun but lost it, and the rest had 38 special snubbies (or were forced to use 3 special snubbies after loosing or going empty with other guns)

The mini-14 rifle ruled the gunfight.

The FBI decided that the solution was to get a more powerful handgun (The real solution was to give agents rifles of their own, and better training) and so they got ahold of the 10mm. But this had too much recoil for many agents. So Smith and Wesson modified it to a less powerful, shorter round called the 40 S&W (which fans of the 10mm auto say stands for short and weak). The original sales pitch was 'the power of a 45 and the capacity of a 9mm. This of course was not true, but it did roughly split the difference between the 9mm and 45acp in power, and did it by giving up just 2 shots to the 9mm.

Where the FBI goes, other police agencies usually soon follow. This is partly due to simply being copy-cats, but also because police agencies will send officers to train with the FBI and then come back and teach what they learned to their own departments. Finally, cops like new shiney equipment. It is hard for a police chief to go to the city council and say 'our current guns are just fine, but we want $200,000 to buy all new ones' However if you say 'look, the FBI says our guns stink because they are 9mm and that is too weak, lets spend $200,000 and get some fancy new 40 SW guns!' then you get more traction.

LEO's are constantly in search of better rounds. Part of the problem is that a pistol round is not really the best manstopper, but it's politically incorrect and/or impractical in most scenarios for them to be carrying something like an assault rifle or shotgun. There have even been some police departments in liberal states that refuse to give their officers an assault rifle - I believe one police chief in a New Jersey township actually refused some AR's that were to be donated to his department.

Why 9mm to .40S&W and not a .45acp? Firstly, not all LE have gone to .40S&W and some still use 9mm and some allows .45acp.. But the main impetus for moving to the .40S&W came out of the FBI study of the infamous shooting in Miami, Florida in 1986 which also pretty much ended the use of revolvers by LEO. Basically, while the .45acp as deemed a better manstopper, the low capacity magazines of pistols in the caliber made it (in their opinion) a liability when faced with criminals armed with large capacity weapons such as the case in the Miami shooting where the criminal was armed with a 30 round Mini-14.

About this time, the 10mm round came to the FBI's attention (one of their analyst owned a Colt Delta Elite) and although they liked it for the velocity and penetration, it was too powerful in terms of recoil and many agents especially female agents simply could not handle it. S&W was contacted to downsize the 10mm and the result is the .40S&W.

So in effect, the .40S&W is a compromise between the 9mm and .45acp for power and magazine capacity. Whether this actually means a more effective round is something that is still hotly debated.

For standardization applications, we used 38 up until eventually seventy 4 then went to 357. In 1990 we went to 9mm and that changed into for fireplace capacity. In 2000 we went to 40 cal for undercover and 9mm prevalent issue. Many have gone to the 9mm with the intention to have the ability to interchange ammunition throughout the time of a shoot out. Use to be hell at the same time as one had 38 yet another 357 and yet another had 9mm rounds. Retired utilising a 40 cal for transportation's.

I asked a LEO firearms training instructor that same question and this is what he told me; he said with the 9 mm they were getting results other than the bad guy hitting the ground. In some cases the smaller faster 9mm was cutting clean through people without transferring its energy into the bad guy, so the bad guy sometimes didn't know he was shot, so he wouldn't stop. They also found instances where bullets would " bounce" off of thick loose clothing, they believe the faster smaller bullet is more likely to be affected by angles of impact. So basicaly they believe the 40 is better at transferring its weight into human targets. They think the slower heavier bullet has a better chance of accomplishing what they need under varying circumstances. Kep in mind, the true object isn't t kill someone, its only to stop them and put them on the ground. So lethality isn't the big issue, its about what performs best, and previous incident reports are what they base their decisions on.

They switched from the .38 Special to the .357 Mag when bad guys started running around in vehicles. The famous FBI shoot out appears to be the reason most law enforcement switched from 9mm to .40 S&W. Obviously law enforcement thinks it is much better to miss with a .40 S&W than miss with a 9mm.

you have to consider there is a lag between seeing a need--- and bringing a product to the market.

LEO agencies were quickly disapointed with 9x19 compared to the 357Mag back in the 80's. Solution: come up with the 10MM that soon evolved into a milder 40SW. The 40 was an effort to approach 357 and 45 ACP performance in a platform with good magazine capacity.

Since... all the major gun makers have tried 357 Sig, 40SW, and many have a good, non-1911 style gun out there. Many major agencies have started allowing 45 ACP again... and the better guns availible make it a good go-to choice for those folks who prefer it to the others.

1. Who told you the main lie to start with? Philadelphia, Nypd, LAPD, And many others use 9mm Paras. Many others use .357 sig like the Secret Service does.

2. What is wrong with the .45 acp? The option has been rejected for a century by most in law enforcement due to it being tied to the M1911a1 as the main gun that used it. It still has too much recoil even in newer gun designs.

3. caliber choice rarely is critical.

My dad used a .38 when he worked for NYPD. The year he retired they switched the the 9mm and still use it. The 9 is still in use by NYPD today I beileve as my brothers trying to get a job as a cop. The caption right now was actually a rookie when my dad worked how funny? Anyway the .40 is more common now a days because well shooting a 9 can actually be dangerous for innocent people around. The .40 on the other hand should deliever a little more of a punch without flying into the next town.

40 actually holds LESS rounds. because each cartridge is wider, a 9mm magazine vs a 40 S&W magazine of the same dimensions, the 9mm holds more and hte 40 holds less.

i believe it's because cops can't shoot due to appallingly low standards (in California it's 65% rounds hit the paper at 15 yards, take all the time you want too) so by making each round more powerful, perhaps when they do manage to hit the bad guy it'll take him down.

45 acp does over penetrate, and missed shots tend to penetrate more thru walls and furnishings and innocent bystanders than 40 or 9mm.