Making 357 sig from 40 S&W brass

Patrick Graham · December 12, 1999, 09:40 AM

Has anyone made 357 sig brass by running 40 S%W brass through 357 sig dies?

flatlander · December 12, 1999, 11:03 AM

Patrick: I just read the other day, somewhere, that you can't get proper dimisioned cases for 357 SIG by using 40 S&W brass. Wish I could remember where & why. Perhaps the cases come up way too short?

Fred · December 13, 1999, 04:09 PM

It can be done. My RCBS .357 Sig dies included a piece of paper that said it could be done, and still maintain "proper functioning". It also noted that the cases would be approx. .018" less in length than .357 Sig brass.

I will tell you that I personally have used reformed .40 brass for LIGHT .357 Sig loads. You can just lube the case, and run it through the regular sizing die. That said, there is merit to sticking with .357 Sig brass for anything other than light loads. My measured re-formed brass was actually .022 to .025" shorter than .357 Sig brass. That's a lot. Also, the .357 brass is supposed to be stronger (thicker) than .40 brass. Given that this round is a fairly high pressure one, I want all the safety margin I can get.

I guess what I'm saying is that, for me, I no longer use .40 brass for this purpose. The price of .357 Sig brass from Starline is reasonable enough that I discontinued my earlier practice.

------------------
Regards - AZFred

[This message has been edited by Fred (edited December 13, 1999).]

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December 12, 1999, 09:40 AM	#1
Patrick Graham Junior member Join Date: January 18, 1999 Location: Kokomo, Indiana USA Posts: 674	Has anyone made 357 sig brass by running 40 S%W brass through 357 sig dies?

December 12, 1999, 11:03 AM	#2
flatlander Senior Member Join Date: June 16, 1999 Posts: 120	Patrick: I just read the other day, somewhere, that you can't get proper dimisioned cases for 357 SIG by using 40 S&W brass. Wish I could remember where & why. Perhaps the cases come up way too short?

December 13, 1999, 04:09 PM	#3
Fred Senior Member Join Date: November 3, 1998 Location: CA Posts: 465	It can be done. My RCBS .357 Sig dies included a piece of paper that said it could be done, and still maintain "proper functioning". It also noted that the cases would be approx. .018" less in length than .357 Sig brass. I will tell you that I personally have used reformed .40 brass for LIGHT .357 Sig loads. You can just lube the case, and run it through the regular sizing die. That said, there is merit to sticking with .357 Sig brass for anything other than light loads. My measured re-formed brass was actually .022 to .025" shorter than .357 Sig brass. That's a lot. Also, the .357 brass is supposed to be stronger (thicker) than .40 brass. Given that this round is a fairly high pressure one, I want all the safety margin I can get. I guess what I'm saying is that, for me, I no longer use .40 brass for this purpose. The price of .357 Sig brass from Starline is reasonable enough that I discontinued my earlier practice. ------------------ Regards - AZFred [This message has been edited by Fred (edited December 13, 1999).]