40 cal v 10mm

The length of the cartridge. It's like a .38 and .357 mag.

They are the same caliber one just the ability to carry more powder and higher pressures.
 
The 40 is a descendant of 10mm. The 10mm auto cartridge was adopted by the FBI after the 1986 Miami shootout. The FBI decided that the recoil of full power 10mm loads was too much for many agents, so they specified a reduced load. Smith and Wesson realized that with the FBI load they didn't need the full case capacity of 10mm. They created the 40 S&W to allow them to build pistols for the FBI loading on the same frame size as 9mm, and now the 40 is far more popular.
 
The shorter .40 cartridge allows for a smaller grip circumference. 10mm allows for a more powerful load if desired.
 
...what is the difference between the two and why do people seem to prefer the 10mm over the 40 caliber? Is it in the loading?

It's all about the load. The bullets are typically the same, except for the 200 grainers, which typically are only found in 10mm Auto loadings. 10mm Auto has a longer
case, usually thicker brass, and a large pistol primer for ignition.

The key technical difference is that .40 S+W "roofs out" pretty quickly- there's literally not a whole hell of a lot of headroom in loading .40 S+W, especially with 180 grain bullets. In .40 S+W said bullet might be cruising around 1050 fps tops at pressure max. In 10mm auto that same bullet can be going well northward of 1200 FPS!!! [grin]

Basically, think of .40 S+W as an intentionally crippled 10mm. It's not that it's a completely terrible cartridge, but it's WAY less versatile than 10mm Auto is, and the maximum
power capability of the 10mm is easily an order or so of magnitude greater than .40 S+W.

-Mike
 
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The bullet diameter is the same. The 40 S&W is just a shortened 10mm case.

True on the former, but not entirely so on the latter. The case head area of the 10mm has a slightly thicker web and it also takes a large pistol primer instead of a small one. Of course I'm being pedantic here, but this is one of the main differences between the two, and it also contributes overall to the difference in capability between the cartridges.

-Mike
 
Is there any compatibility between the two calibers, like there is between .38 special and .357 magnum (i.e. you can shoot .38 special from a .357 magnum revolver)?
 
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Is there any compatibility between the two calibers like .38 special and .357 magnum (i.e. you can shoot .38 special from a .357 magnum revolver)?

Yes, you can shoot .38 Special in a .357 Magnum revolver (but not the reverse). The same is true for .44 Special and .44 Magnum.
 
Yes, you can shoot .38 Special in a .357 Magnum revolver (but not the reverse). The same is true for .44 Special and .44 Magnum.

Sorry, my question was ambiguous. I was asking, does the 10mm and .40 S&W share the same compatibility that calibers like .38 special and .357 magnum do? Is there a gun chambered in 10mm that can shoot .40 S&W?

I imagine in an automatic there would be some problem with chamber size and extraction, but it doesn't hurt to ask, I suppose.
 
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Sorry, my question was ambiguous. I was asking, does the 10mm and .40 S&W share the same compatibility that calibers like .30 special and .357 magnum do? Is there a gun chambered in 10mm that can shoot .40 S&W?

S+W 610 series wheelgun will shoot both. IIRC with autos the springfield omega was the only one that could handle both at once without a barrel change, and that gun has basically gone into dodo bird land for support.

-Mike
 
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The platform is different except for the barrel ( caliber. ) The .40 Short and Weak uses the 9mm sized frames for their basis. The 10mm Auto would be closer to the .38 Super for frame size than .45, at least on the 1911 platforms. You couldn't fit a 10mm in a 40 S&W mag and the other way would leave a jump into the ramp/chamber + the round probably won't headspace well and would lead to accuracy problems.

Joe R.
 
The platform is different except for the barrel ( caliber. ) The .40 Short and Weak uses the 9mm sized frames for their basis.

Overbroad and inaccurate as stated.

GLOCK
"uses the 9mm sized frame for their [sic] basis [sic]." It does so by undercutting the chamber to fit the feedramp into the too-short frame, leading to the occasional, but spectacular, "Ka-Boom" for which .40 Glocks are notorious.

1911's chambered in .40 (and they are legion) build on the standard .45 frame (which is why many .40 shooters "load long"). Smith & Wesson uses a larger frame for its .40 and .45 M&P's and Chief's Special pistols than it does for the 9mm versions of those models.

Note also that the barrel is NOT the same for .40 and 10 mm. As the latter is longer, thus requiring a different chamber, it necessarily follows that each caliber requires its own barrel if the gun is an autoloader.
 
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357Sig10mm40sw.jpg


.357 Sig, 10mm, .40 S&W
 
Does the 357 Sig have the same Glock kBoom potential as the 40? Looks (by eyeball, anyway) to be roughly the same OAL & brass diameter as the 40.

What's out there for MA available 10mm pistols these days, anyway? I see the occasional Glock 20 - anything new?
 
The .357 SIG is essentially a .40 S&W necked down to take a 125 grain, 9mm bullet. The object of the exercise was to duplicate the .357 Magnum 125 JHP in an auto cartridge.
 
There are glock 29s out there too. The S&W 610 revolver (shoots both 40S&W and 10mm) is on the list, but I don't know if it's the current variant.
 
There are glock 29s out there too. The S&W 610 revolver (shoots both 40S&W and 10mm) is on the list, but I don't know if it's the current variant.

Yeah, the current 610's are OK in Mass (they're still 610-3s).

There's a very simple way to prevent a kB in a Glock: replace the stock barrel with a good aftermarket one from Lone Wolf or KKM Precision (my favorite). The aftermarket barrels do not have polygonal rifling and offer much better case head support in the chambers.

KKM also sells conversion barrels. I have a 10mm barrel for my G30 (.45ACP). All I need to do to switch from .45ACP to 10mm is to swap the barrels and magazines (for 10mm you use G29 mags).
 
I have the same set up in an AO 1911 10mm, except I change the slide and barrel. The 1911 based 10mm uses standard .45acp mags, but it will hold 8 instead of seven.

Yeah, the current 610's are OK in Mass (they're still 610-3s).

There's a very simple way to prevent a kB in a Glock: replace the stock barrel with a good aftermarket one from Lone Wolf or KKM Precision (my favorite). The aftermarket barrels do not have polygonal rifling and offer much better case head support in the chambers.

KKM also sells conversion barrels. I have a 10mm barrel for my G30 (.45ACP). All I need to do to switch from .45ACP to 10mm is to swap the barrels and magazines (for 10mm you use G29 mags).
 
Overbroad and inaccurate as stated.

GLOCK
"uses the 9mm sized frame for their [sic] basis [sic]." It does so by undercutting the chamber to fit the feedramp into the too-short frame, leading to the occasional, but spectacular, "Ka-Boom" for which .40 Glocks are notorious.

1911's chambered in .40 (and they are legion) build on the standard .45 frame (which is why many .40 shooters "load long"). Smith & Wesson uses a larger frame for its .40 and .45 M&P's and Chief's Special pistols than it does for the 9mm versions of those models.

Note also that the barrel is NOT the same for .40 and 10 mm. As the latter is longer, thus requiring a different chamber, it necessarily follows that each caliber requires its own barrel if the gun is an autoloader.

My intention was to be overly broad. He didn't ask specifics so I kept it general.

Joe R.
 
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