.40 S&W = 10mm ?

robhic · March 16, 2020, 03:19 PM

Please excuse my ignorance but I am considering buying a reloading die set for my grandson who owns a .40. First, I need to see if he's onboard but I'm considering getting a die set for him (yeah, I'm a good grandpaw...) and letting him use the dies to reload on my equipment. I don't have any .40 cal stuff so I am completely ignorant about it.

I saw some 40S&W/10mm sets but I don't want to get 10mm. Is this the same as 40S&W? I'm thinking I'd get the dies and teach him using my manuals, powder and primers. He'd need to furnish casings and bullets. I have NONE.

I didn't know 40S&W was even close to 10mm but live and learn (I guess...).

So if he wants to give it a go, can I get the 40/10mm set and teach the boy all my bad techniques?

Thanks!

jaguarxk120 · March 16, 2020, 03:26 PM

The 40 S&W and the 10MM are the same case diameter. That said, the 10 MM case is longer than the 40.
So the same die set can be used to load both cartridges.
Just resetting the bullet seater die.

Marco Califo · March 16, 2020, 04:02 PM

Yes, same dies. I like the Lee dies in sets that include the factory crimp die. A powder through expander die is also very useful. The 4 die set is $45 at MidsouthshootersSupply.com 40 S&W Deluxe Pistol Carbide 4 Die Set With Shellholder

gwpercle · March 16, 2020, 05:57 PM

Think about the 38 special / 357 magnum . The only difference between them is the slightly longer case of the 357 magnum... you can reload both with 38 special dies by adjusting the dies for the longer 357 round . If dies are simply marked 357 magnum they can not be used to load the shorter 38 special. Most dies are now made and marked
38 spcl./ 357 mag. and will do both .

Same applies to 40 S&W and 10 mm Auto ... the 40 S&W being the shorter and the 10mm being longer . If a die set is marked 40 S&W / 10 mm Auto it can be used to reload both by adjusting the seating and crimping dies . Some sets have a spacer included to help with the die adjustment to 10 mm Auto .

He's lucky to have a Dad who will show him how it's done.
Good Luck ,
Gary

Nick_C_S · March 17, 2020, 12:21 AM

The 10mm and 40 S&W use the same dies and shellholder - as has already been mentioned.

The 10mm uses a large primer, however. The 40 uses a small primer.

Hope your grandson has been saving his brass cases.

robhic · March 17, 2020, 03:32 PM

Thanks to all for the information. That's kinda what I was thinking (like.38spl and .357mag). My RCBS dies have a spacer washer to lengthen the .38 for the .357 use. Good deal.

Now I need to interrogate him and make sure he would keep reloading and not leave me with the .40S&W stuff as I have none ... and don't really want it. He just bought the gun a couple of months back and got his carry permit, too.

I'm gonna remind him to save the casings when he goes out without me. I already gave him a bag to put in his 9mm and .45acp cases for me. I gave him a Beretta 92s (one of those Italian police/military trade ins) and a Glock G30 .45 I could not shoot accurately

but he shoots like a boss.

I guess next he'll want to use my 9 and .45 dies! Thanks again for the info now just to see what he says.

March 16, 2020, 03:19 PM	#1
robhic Senior Member Join Date: November 3, 2016 Location: Outside of New Orleans, LA. Posts: 313	.40 S&W = 10mm ? Please excuse my ignorance but I am considering buying a reloading die set for my grandson who owns a .40. First, I need to see if he's onboard but I'm considering getting a die set for him (yeah, I'm a good grandpaw...) and letting him use the dies to reload on my equipment. I don't have any .40 cal stuff so I am completely ignorant about it. I saw some 40S&W/10mm sets but I don't want to get 10mm. Is this the same as 40S&W? I'm thinking I'd get the dies and teach him using my manuals, powder and primers. He'd need to furnish casings and bullets. I have NONE. I didn't know 40S&W was even close to 10mm but live and learn (I guess...). So if he wants to give it a go, can I get the 40/10mm set and teach the boy all my bad techniques? Thanks! __________________ - Robert

March 16, 2020, 04:02 PM	#3
Marco Califo Senior Member Join Date: April 4, 2011 Location: LA (Greater Los Angeles Area) Posts: 2,598	Yes, same dies. I like the Lee dies in sets that include the factory crimp die. A powder through expander die is also very useful. The 4 die set is $45 at MidsouthshootersSupply.com 40 S&W Deluxe Pistol Carbide 4 Die Set With Shellholder __________________ ............

March 17, 2020, 12:21 AM	#5
Nick_C_S Senior Member Join Date: March 21, 2013 Location: Idaho Posts: 5,522	The 10mm and 40 S&W use the same dies and shellholder - as has already been mentioned. The 10mm uses a large primer, however. The 40 uses a small primer. Hope your grandson has been saving his brass cases. __________________ Gun control laws benefit only criminals and politicians - but then, I repeat myself. Life Member, National Rifle Association

March 17, 2020, 03:32 PM	#6
robhic Senior Member Join Date: November 3, 2016 Location: Outside of New Orleans, LA. Posts: 313	Thanks to all for the information. That's kinda what I was thinking (like.38spl and .357mag). My RCBS dies have a spacer washer to lengthen the .38 for the .357 use. Good deal. Now I need to interrogate him and make sure he would keep reloading and not leave me with the .40S&W stuff as I have none ... and don't really want it. He just bought the gun a couple of months back and got his carry permit, too. I'm gonna remind him to save the casings when he goes out without me. I already gave him a bag to put in his 9mm and .45acp cases for me. I gave him a Beretta 92s (one of those Italian police/military trade ins) and a Glock G30 .45 I could not shoot accurately but he shoots like a boss. I guess next he'll want to use my 9 and .45 dies! Thanks again for the info now just to see what he says. __________________ - Robert

March 16, 2020, 03:26 PM	#2
jaguarxk120 Senior Member Join Date: February 28, 2008 Location: Michigan Posts: 2,619	The 40 S&W and the 10MM are the same case diameter. That said, the 10 MM case is longer than the 40. So the same die set can be used to load both cartridges. Just resetting the bullet seater die.

March 16, 2020, 05:57 PM	#4
gwpercle Senior Member Join Date: November 30, 2012 Location: Baton Rouge, Louisiana Posts: 1,752	Think about the 38 special / 357 magnum . The only difference between them is the slightly longer case of the 357 magnum... you can reload both with 38 special dies by adjusting the dies for the longer 357 round . If dies are simply marked 357 magnum they can not be used to load the shorter 38 special. Most dies are now made and marked 38 spcl./ 357 mag. and will do both . Same applies to 40 S&W and 10 mm Auto ... the 40 S&W being the shorter and the 10mm being longer . If a die set is marked 40 S&W / 10 mm Auto it can be used to reload both by adjusting the seating and crimping dies . Some sets have a spacer included to help with the die adjustment to 10 mm Auto . He's lucky to have a Dad who will show him how it's done. Good Luck , Gary