.40 S&W necked down to 9mm brass

[bartlet33]

I have a bunch of .40 S&W brass necked down to 9mm. Some might call this .357SIG. Is this true? Further, can this brass be reformed back to .40 S&W?
Surely some one out there has tried it.

 

[MrSchultz]

I know a fellow shooter that uses 40 brass for his 357sig. It's much easier to find this brass compared to the 357sig. He appears to have no issues with his loads.

 

[Canuck223]

If you run .40 brass through .357 Sig dies, your brass will come up a bit short. It's possible to do, but it means less case mouth tension, and you'll need to adjust your dies to headspace the cases off the shoulder as the mouth won't be long enough.

There is also a 9/40 chambering, similar in dimentions but meant for the .40 case.

 

[daBear]

Often referred to as 9x40, it is similar to 357SIG but not identical. True 357SIG has a slightly longer neck making for more surface tension on the bullet. Some may also want to go on about the headspace issue resulting but I am not going to get into that(mouth vs shoulder). Some claim that the home made 9x40 is not as strong as the 357SIG brass as the true 357SIG brass is built to withstand higher pressures. However, those who make their own dont seem to load it more than 1 or 2x before its left scattered at the range. Given the cost of true 357SIG, it is an ecomical alternative but a practice that is also shunned by some. I have loaded both and it sure is nice to have the extra neck length found on the real stuff.
dB

I gotta type faster....