10mm and .40 S&W , what the difference???

[1911Operator]

hey guys, its me again, the newbie to reloading. I am about to order my dilon 550b next week, and im selling my .40 SW990L. I have been looking around for bullets and I keep seeing 10mm and .40 together. Does that mean that a 10mm projectile can be shot out of a .40 S&W gun and brass casing? I have seen a .401 and a .410. can anyone clarify this for me? If its ok to shot then I might be keeping my SW990L, I have been seeing really cheap prices of the components!

[joelogic]

my understanding is they are the same size bullet. .410 is a shotshell round.

[SixPointEight]

.401 is the size of a .40/10mm projectile. The casing on the 10mm is longer that of the .40. Also, 10mm uses a LPP and .40 uses SPP

ETA: .401 is the size of a plated or lead bullet. I believe you'd be using .400 bullets if they are jacketed.

[mif_slim]

10mm is longer, same projectile though. Thats about it...

[sargenv]

Nominal load for 40 S&W is a 180 gr bullet at about 980 feet per second

Original nominal load for a 10 mm is a 200 gr bullet at 1200 feet per second (as loaded by Norma).

The FBI wanted the 10 mm but found that their agents couldn't handle the recoil, so they developed a reduced load 10 mm that was a 180 at 980 fps. Winchester shortened the cartridge, made it have the same ballistics as the FBI reduced 10 mm load and dubbed it the 40 S&W.

Or at least that's how I remember it, in simple terms.. I'm sure there was more to it, but that is the basics of how it happened.

[XDRoX]

Nominal load for 40 S&W is a 180 gr bullet at about 980 feet per second

Original nominal load for a 10 mm is a 200 gr bullet at 1200 feet per second (as loaded by Norma).

The FBI wanted the 10 mm but found that their agents couldn't handle the recoil, so they developed a reduced load 10 mm that was a 180 at 980 fps. Winchester shortened the cartridge, made it have the same ballistics as the FBI reduced 10 mm load and dubbed it the 40 S&W.

Or at least that's how I remember it, in simple terms.. I'm sure there was more to it, but that is the basics of how it happened.

I've heard this as well. Wonder if it actually true? I'll keep telling it as well until I hear different

[SixPointEight]

I've heard this as well. Wonder if it actually true? I'll keep telling it as well until I hear different

Your username reminds me of another difference. They don't make an XD in 10mm.

And I've heard the same story. At some point, if we all hear it, it will HAVE to be true

[Malthusian]

If I might add:

The 40 S&W uses small pistol primers
The 10mm uses large pistol primers

[XDRoX]

If I might add:

The 40 S&W uses small pistol primers
The 10mm uses large pistol primers

There are some newer 45's that use small pistol primers. I need to get some.

[hill billy]

When loaded properly, the 10mm can be moving about 250-300 FPS faster.(or more) Speed=damage upon impact.

[Revoman]

If you think about the difference between a 38 special and a 357 magnum, then you will understand what the difference is.

When loading 38 or 357, you use the same diameter bullets. The same holds true for 40 or 10. Your gun must say 10 mm on it in order to shoot a 10, very much like a 357, which states "357 magnum" on the gun.

You can shoot 40 out of a 10 and a 38 out of a 357, but you cannot reverse those. The more powerful 357 and 10 can ruin your day if shot out of the wrong firearm.

[FTC]

.410 is the projectile for a 41 remington magnum

and i wouldnt try to shoot 40s&w out of a 10mm pistol.
they headspace off the case mouth

[SixPointEight]

If you think about the difference between a 38 special and a 357 magnum, then you will understand what the difference is.

When loading 38 or 357, you use the same diameter bullets. The same holds true for 40 or 10. Your gun must say 10 mm on it in order to shoot a 10, very much like a 357, which states "357 magnum" on the gun.

You can shoot 40 out of a 10 and a 38 out of a 357, but you cannot reverse those. The more powerful 357 and 10 can ruin your day if shot out of the wrong firearm.

Bad advice. Is it possible to shoot a .40 in a 10mm? Yes, it's been done. Is it acceptable to do so like it is shooting .38 in a .357? NO!

[Fjold]

The 40 S&W was shortened from the 10MM by S&W so that it would fit in the grip length (not height) as the guns that were already built to fit the 9mm cartridge. It saved them from having to design and retool for another magazine length.

You should not shoot 40 S&W ammunition in a 10mm gun because both rounds headspace on the case mouth and the 40 S&W case is to short to headspace properly.

The 38 special and 357 mag both headspace on the rim (which is the same for both cartridges) so the shorter 38 special case will still headspace in the 357 Mag chamber.

[Revoman]

Thanks you for the correction gents...........that's why my name is Revoman, not Automan!

I can shoot both of these rounds out of my S&W Model 610 REVOLVER, thus the post. Not thinking too much about the auto pistola's.

Sorry for the mis-information as apparently the OP is using an auto.