357 sig from 40 brass

Has anybody else loaded 357 sig with 40 s&w brass. It is supposed to headspace on case mouth but being a bottleneck case ought to headspace on the reduced section like a rifle ctg. I tried this and with a 100 grain berrys 100 gn rn fmc ran a couple hundred through a USP 357 barrel without a hickup or set back bullet. Cheap and dirty brass for range use only. only had to be extra carefull to not expand any more than enough to get bullet started. Shooting range use only. I have never even had a factory round for this barrel.Shoots great but a noisy sucker.

I could be wrong, but I believe .357 SIG brass formed from .40 S&W cases will be a tad or two tads short.

And the .357 SIG headspaces on the case mouth.

It will work, if your extractor holds the primer close enough to the breech-face for the firing pin to reach it.

But it is not at all an ideal situation.

rc

New cases headspace on bottleneck like rifle cases. anyway die was screwed all the way in to get case to end of chamber so cases probably headspace on bottleneck in real life. Yes case is 20 -30 thousandts short in neck wich is why care is taken to expnd only start of neck.no setback observed to date.

I believe Uncle Don made many thousands of .357 Sig brass from .40.

Uncle Don, where are you?

http://i231.photobucket.com/albums/ee304/SteveKoski/GP%20Pics%20A/BatAlertUDLoadmaster.jpg

Case mouth? Shoulder? Who cares as long as it works. Just make sure you're not overworking the cases. You might wanna experiment with backing out your die to see if you can still fit a case without sizing it all the way.

When I loaded 357 Sig, I made them from 40 brass. It's true that the neck was too short, but when formed from 40s it headspaced on the shoulder so it worked OK. I used 90gr bullets so the short neck was fine. 357 brass is supposed to be stronger, but this isn't an issue for plinking loads.

It does work and like anybody else is saying it is will be short.
Just don't max them out cuz a 357 sig is 40k psi and a .40 SW is 35k psi