The Versatible 10mm

Am Shooting Journal ^ | 7/7/2021 | J Brooks

[w1n1]

First developed to combine the attributes of the 9mm Luger and the .45 ACP, this round is now one of the best handgun hunting cartridges made for semiautomatics.
Handgun shooters know that two of the most popular calibers are the 9mm Luger (Parabellum) and the .45 ACP. The latter is slow but makes a big hole, while the faster 9mm tends to lose energy quickly once it hits the target but shoots fast and flat. In a perfect world, a gunmaker would bridge these two rounds to make a fast and hard-hitting bullet.

It is this very idea that led Lieutenant Colonel John "Jeff" Cooper to come up with what we now know as the 10mm Auto. Back in 1983, the search began by looking at the speed of the 9mm Luger and the energy of the .45 ACP. The idea was that if a round could shoot fast, which means flatter trajectory, and could hit hard, then it would fit the military’s need, as well as that of law enforcement and civilian use for self-defense. The 10mm was created by taking a .30 Remington rifle case and cutting it down to .992 inch and opening the mouth large enough to seat the 10mm (.400-inch) bullet.

Overall length is 1.240 inches up to an acceptable 1.260 inches. The round shoots 180-grain bullets very well, but loads are available for lighter and faster projectiles down to 135 grains, which shoot nearly 400 feet per second faster than the 115-grain bullet out of a 9mm. It is also loaded with 200-grain powerhouses that shoot around 300 fps faster than the 230-grain .45 ACP. It seems that Lt. Col. Cooper was onto something when the 10mm was developed.

FIRST CALLED THE 10mm Super, the cartridge never really shined. This could be because there was already a 10mm Super on the market so a name change had to be made; this set back the rise to fame, as shooters didn’t know what the 10mm was all about. In 1989, the FBI decided to issue the 10mm to their agents. This occurred after the shootout in Miami, Florida, in which five FBI agents were injured and two were killed when they attempted to arrest two bank robbers. The agents were armed with .357 Magnums and .38 Specials, both revolvers.
After the incident the FBI realized they needed more firepower in their issued sidearms, both in ammo capacity and in bullet performance. Through testing, and like Lt. Col. Cooper, they decided the 10mm fit their needs. But there was one reason why the military and even the civilian world never really accepted the 10mm and that was felt recoil A fast and heavy round means there will be a bit of push back when you pull the trigger.

Smaller-framed agents couldn’t handle the recoil of the 10mm. When it comes to law enforcement, it is more important to hit your target with a light-shooting bullet than miss with a heavy one. For personal defense, a lot of times just producing a handgun will stop the encounter and then the loud bang could thwart the criminal. But for law enforcement, where each round has to be accounted for, it is imperative that the intended target is hit.
Because of this, the FBI decided to go with another new round on the market, very similar to the 10mm, the .40 Smith & Wesson (S&W). The .40 S&W was built on the 10mm case and bullet, using the same 10mm projectile but in a shorter case that held less powder, shot slower and therefore had less recoil. Most law enforcement departments today use the .40 S&W. Read the rest of versatile 10mm here.

[Yo-Yo]

Most law enforcement departments today use the .40 S&W.

With the FIB going back to the 9mm, departments nationwide have been dropping the .40 Short and Weak in droves.

I'd challenge that "most law enforcement departments today" assertion.

[AlaskaErik]

The Glock 20 10mm is the go-to pistol in Alaska today for bear defense. The only point of contention is which ammo to use. One side believes heavy slugs, like the Buffalo Bore 220 gr is the way to go. The other side believes a lightweight penetrating round like the Xtreme Penetrator 140 gr is the way to go. But only older bitter clingers believe a large-frame revolver is better.

[Yo-Yo]

https://www.policemag.com/502150/9mm-caliber-of-choice

[AlaskaErik]

With the FIB going back to the 9mm, departments nationwide have been dropping the .40 Short and Weak in droves.

I haven't heard of a single agency in Alaska that's gone to the 9mm. It's more likely places with a "diverse" police force have switched to 9mm. NYPD would be a perfect example.

[G Larry]

Ya, as soon as you can find ammo again and stock up on about 5000 rds....10mm might be a good idea.

[Dead Corpse]

10mm is best millimeter.

[Salamander]

I thought this thread was about the always-missing socket.

[circlecity]

“I'd challenge that "most law enforcement departments today" assertion.”

Agreed. Many many police departments have returned to 9mm after the landmark 2015 FBI study which destroyed the “stopping power” myth of 40 cal and 45 acp.

[chief lee runamok]

AKA: shotgun shell from hell.

https://youtu.be/YkL8q9_Jnj0

[Myrddin]

The Ruger SR1911 in 10mm is a very comfortable way to shoot any 10mm cartridge. For greater magazine capacity, the Springfield XDm 10mm 5.25" barrel, 15+1 mag is a better choice in bear country. Ruger's GP100 10mm, 6 shot with 3" barrel and Novak sights is a satisfactory CCW.

[vpintheak]

This Alaskan agrees!

[TexasGator]

“The Glock 20 10mm is the go-to pistol in Alaska today for bear defense.”

Only by some.

[TexasGator]

“For greater magazine capacity, the Springfield XDm 10mm 5.25” barrel, 15+1 mag is a better choice in bear country.”

16 rounds at a charging bear?

[TexasGator]

“But only older bitter clingers believe a large-frame revolver is better.”

1600 ftlbs is better!

[blueunicorn6]

I always carry a Killer Whale in Grizzly country.

[Seruzawa]

The word is “Versatile”.

[Cold Heart]

LOL, I am missing a 10mm socket

[griffin]

Eagerly awaiting my XDm OSP on 10mm.

[DOC44]

“The Glock 20 10mm”

This is my everyday carry pistol along with a second mag as well as my sidearm when hunting. 30 rds of 10mm should handle a lot of situations.