Why the FBI Created the .40SW

[Hohn]

Or, the 10mm (Fbi Special) as it was then known.

Here is the FBI's publication from November 1989 that documented the testing that led to the adoption of the "10mm" by the FBI.

Some interesting observations:

The tested FBI load that was voted overall best performer was 180gr at only 950fps. What are the typical .40SW loads at in 180gr?
- Speer Gold Dot: 1025fps
- Ranger T: 990fps
- Federal HST: 1010fps
- Speer "short barrel": 950fps

Interesting that the Speer short barrel is exactly the same specs as the load the FBI whipped up for the 10mm testing.

Do read all of the report. Especially the part about extra power in the round just giving more recoil and muzzle flash without any increase in ballistic performance.

http://dl.dropbox.com/u/51346644/FBI-10mm.pdf

 

[AuburnGuy]

Interesting read. Thanks for sharing.

 

[BigMoose]

In it's TRUE 1300fps loading 10MM is an auto cartridge that can put many revolvers to shame. It's also a cartridge you can hunt with.

By the time you knocked it down to 950FPS, well you might as well shorten the case to avoid all the expensive mods and lengthened frames needed for the 1300fps loads.

 

[Panama]

The 10mm is an AWESOME round, especially with hand loads or even today's commercially available rounds.

Compare the FBI tested ammo data, to the ammo available today from Underwood Ammo

Technical Information

• Caliber: 10mm Auto
• Bullet Weight: 135 Grains
• Bullet Style: Nosler Jacketed Hollow Point
• Case Type: Brass
  
  Ballistics Information:
• Muzzle Velocity: 1600 fps
• Muzzle Energy: 767 ft. lbs.

______________________________________

• Caliber: 10mm Auto
• Bullet Weight: 155 Grains
• Bullet Style: Speer Total Metal Jacket
• Case Type: Brass
  
  Ballistics Information:
• Muzzle Velocity: 1500 fps
• Muzzle Energy: 775 ft. lbs.

_____________________________________

• Caliber: 10mm Auto
• Bullet Weight: 200 Grains
• Bullet Style: Jacketed Hollow Point
• Case Type: Brass
  
  Ballistics Information:
• Muzzle Velocity: 1250 fps
• Muzzle Energy: 694 ft. lbs.

 

[Hohn]

Yeah, the original Norma spec for 10mm was 200 gr round moving at 1200fps. That was the spec Jeff Cooper initiated.

You can see how that would have been pretty hot.

What I find interesting is that the extra power with a 180 gr round didn't translate into additional ballistic performance.

If bullet designers ever came up with a round optimized for the faster speed of the full power 10mm round, you'd have some justification for using the 10mm. I'm thinking particularly a hardcast 200gr or 220gr like Bufalo Bore offers. Those are easily .41mag power range round and plenty for hunting.

But with personal defense ammo, there just aren't yet good rounds opimized for the speed.

Look what happens to a 180gr Gold Dot when you kick it up to full 10mm power levels:
http://www.youtube.com/watch?v=sl_n_miLfbY&feature=share&list=PL04F5D87436EEDCA8

 

[BigMoose]

10MM out of a Carbine is mucho fun too.

It's gets a hefty FPS bump.. (more of an FPS bump then even 9mm or 40S&W)

Thureon Defense "GA" Carbine | Thureon Defense

The FBI actually modded a Thompson auto for 10MM, I once saw a report on it. The results were amazing, but the gun was nigh uncontrollable in full auto.

 

[Hohn]

Here's a stunning video of the G20 with a Mech-Tech carbine conversion. 2000fps with a 135gr Nosler load from Underwood!!

http://youtu.be/GUyQ-E9aEnI

 

[SIGnature45]

Love to learn new stuff. Thanks for posting.

 

[9mmfan]

Good read. If the FBI were ever to revisit the 10 mm, they would be wise to choose the G20 or 29. My 20 is very controllable monster.

 

[willie53]

Hohn, great video on the Underwood, learned more than I knew before

 

[zclevenger]

very interesting read, its great to learn some new things

 

[firecadet613]

Great read! Thanks.

 

[BigMoose]

Good read. If the FBI were ever to revisit the 10 mm, they would be wise to choose the G20 or 29. My 20 is very controllable monster.

That was part of the issue, the tests the FBI did were with 45ACP redone to handle 10MM. Notably a 1928 Thompson and a M1911A1 frame. Later they used the Smith & Wesson Model 1076 and Model 1026.

None of them are decent when handling 10MM. Apparently the Thompson in 10MM was more uncontrollable then a stock select fire M14.

All of these designs used beefed up slides and heavy springs that make the recoil worse then it needs to be. Particularly the Thompson. The Thompson 10MM bolt was massive, and that thing rattling around in there made the smg jump all over the damn place. The S&Ws had heavy slides and made the recoil seemingly worse.

Colt has redone the Delta Elite over several times throughout the year trying to handle this stout round, I wonder how those guns handle now.

 

[cosermann]

Interesting doc. I don't think I had seen that particular one yet. There was a lot going on politically and behind the scenes at the bureau then too, much of which played into the choice of the 10 mm. The .45 ACP also met their criteria, but it was felt that the .45 was an older cartridge, and perhaps developed to it's limit, while the 10mm was a newer cartridge with potential for future development (and the 10mm offered higher mag capacity).

One thing that puzzles me (and I don't know why it was done), was to test a 185 gr bullet for .45 ACP rather than a 230 gr bullet. It would have better matched the sectional densities of the other calibers tested (i.e. 147 gr 9mm, and 170 gr 10 mm).

Anyway, lots has happened since these tests were done in terms of propellant and bullet development (and even round development - the .40 S&W). It would be interesting to see the results if they were redone today; especially since they thought that then-existing 45 and 9mm loads couldn't be significantly improved on - which they HAVE been since - diminishing the differences between service caliber performance. It was then thought that just about everything that could possibly be tried had been tried to improve the performance of the 9mm. Funny/ironic how that's been proven wrong over the last 23 or so years.

Here's another interesting doc:
http://www.firearmstactical.com/pdf/fbi_10mm_notes.pdf

Notice it's the 10mm that's universally mentioned; not the .40 S&W - which came along later to duplicate the performance of a the FBI's reduced velocity 10mm load (after the recoil proved too much for some agents) in a smaller form factor.

See also:
http://www.firearmstactical.com/pdf/fbi-hwfe.pdf

Good history on how we got to where we are with respect to defensive handgun ammunition.

 

[Hohn]

Notice it's the 10mm that's universally mentioned; not the .40 S&W - which came along later to duplicate the performance of a the FBI's reduced velocity 10mm load (after the recoil proved too much for some agents) in a smaller form factor.

You know, busting myths like this is one of the main reasons I posted the OP. The reduced velocity had NOTHING TO DUE WITH BEING ABLE TO HANDLE IT.

It had to do with the tradeoff between recoil, muzzle flash, and terminal ballistics. The FBI testing showing that speeds over 950fps don't really do much for you in terms of ballistics. All they do is add recoil and muzzle flash- at least using the combinations of powders and such that they tested.

There never was a full-power 10mm fielded by the FBI. Period. Dot. End of Story. The FBI had a large volume of test data the showed 950fps to be roughly "optimal" for what they wanted-- not coincidentally very similar to the .38spl 157 gr loads that had been the FBI standard for decades.

Your typical FBI agent actually has no problem handling the recoil of a standard 10mm round, as they put a lot more rounds down range than the typical civilian does.

So please-- stop slandering the FBI by perpetuating the myth that they weren't as manly as those real studs that carry full-power 10mm. They simply ran the tests and followed the data, which suggested that more speed was past the point of diminishing returns.

 

[CB45]

You know, busting myths like this is one of the main reasons I posted the OP. The reduced velocity had NOTHING TO DUE WITH BEING ABLE TO HANDLE IT.

It had to do with the tradeoff between recoil, muzzle flash, and terminal ballistics. The FBI testing showing that speeds over 950fps don't really do much for you in terms of ballistics. All they do is add recoil and muzzle flash- at least using the combinations of powders and such that they tested.

There never was a full-power 10mm fielded by the FBI. Period. Dot. End of Story. The FBI had a large volume of test data the showed 950fps to be roughly "optimal" for what they wanted-- not coincidentally very similar to the .38spl 157 gr loads that had been the FBI standard for decades.

Your typical FBI agent actually has no problem handling the recoil of a standard 10mm round, as they put a lot more rounds down range than the typical civilian does.

So please-- stop slandering the FBI by perpetuating the myth that they weren't as manly as those real studs that carry full-power 10mm. They simply ran the tests and followed the data, which suggested that more speed was past the point of diminishing returns.

Glad somebody said it.

Lots of threads end up sounding like gun shop rumor mills.

That gets old.

 

[shibumiseeker]

Colt has redone the Delta Elite over several times throughout the year trying to handle this stout round, I wonder how those guns handle now.

Quite nicely. If I loaded a hot 10mm round in mine and a +P .45acp round in a similar 1911 you'd hardly be able to tell the difference. I still prefer my G20 and 29 but my newer (2 year old) CDE is very controllable.

You know, busting myths like this is one of the main reasons I posted the OP. The reduced velocity had NOTHING TO DUE WITH BEING ABLE TO HANDLE IT.

It had to do with the tradeoff between recoil, muzzle flash, and terminal ballistics. The FBI testing showing that speeds over 950fps don't really do much for you in terms of ballistics. All they do is add recoil and muzzle flash- at least using the combinations of powders and such that they tested.

There never was a full-power 10mm fielded by the FBI. Period. Dot. End of Story. The FBI had a large volume of test data the showed 950fps to be roughly "optimal" for what they wanted-- not coincidentally very similar to the .38spl 157 gr loads that had been the FBI standard for decades.

Your typical FBI agent actually has no problem handling the recoil of a standard 10mm round, as they put a lot more rounds down range than the typical civilian does.

So please-- stop slandering the FBI by perpetuating the myth that they weren't as manly as those real studs that carry full-power 10mm. They simply ran the tests and followed the data, which suggested that more speed was past the point of diminishing returns.

As it was during that era given the powder/bullet combinations they were testing. What screwed the Norma 10mm was ignoring the flexibility the platform gave. The FBI was right in a lot of ways, the .45acp had little room for development especially as the ammunition had to remain backwards compatible with older weapons, while the 10mm had a lot of growth room. The .40S&W was maxed from the start which meant it didn't have much space to grow. Especially as a pistol/carbine/SMG combination, 10mm gives a wide range of CQB capability and I would love to see the level of development devoted to it as has the 9mm over the years.

I started shooting 10mm with the G29 and the Glock platform makes the 10mm very controllable. Yes, it's more punch than someone who only shoots 9mm or .38spl is used to, but not significantly more than someone shooting a .45 or .357 is used to. I am almost as accurate and fast with my 10mms as I am with my .22lr target pistols, the latter which I practice with way more.

 

[Hohn]

A CQB platform based on a full power 10mm round would be quite interesting. With a 200gr FMJ, you'd have serious penetration potential. That's considerable sectional density for an autopistol caliber. Nevermind a 220gr buffalo Bore hardcast!

While a full-auto would likely be uncontrollable, I suspect a 3-5 round burst mode could be both amazingly capable and controllable.

JH

 

[cosermann]

Here's an interesting thread I read several years ago (and forgot parts of).

Several of the posters are old FBI guys with some interesting insights into some of the intra-agency goings on at the time.

F.B.I. why .10mm. over .45ACP. ?

You know, busting myths like this is one of the main reasons I posted the OP. The reduced velocity had NOTHING TO DUE WITH BEING ABLE TO HANDLE IT. ...

Heh, heh. Yeah, I know that. Not sure why I typed what I did. One reads so much that is a mixture of truth and error that sometimes the BS filter goes down and things slip out. Glad you spotted it.

 

[toomuchfun57]

Good info thanks for sharing