357 Sig necked up to 40 S&W

[Floppy_D]

By sheer accident, I loaded two 357 Sig rounds as 40 S&W (my attention when loading is checking the powder on the top of a stroke, and checking the primer towards the bottom of a stroke... I'm not real concerned with the brass, as I see it come powder stage.)

I cast my bullets in batches, so I know that they are the same, and I usually am more careful with my brass, but a friend helped me sort this, and may have missed a few. One way or another, OAL was good and no neck issues. Looks like a 40 with the wrong headstamp. Knowing this, I might not toss all 357sig brass into the scrap yard bucket.

Anyone had bad luck with 357 necked back to 40?

 

[Loomis]

Are your 40s necked down to 357?

 

[grendelbane]

I have never tried this. I would think that a 357 SIG case necked up to .40 would be a tad bit long. You mentioned the OAL, but not the case length.

Pure conjecture on my part.

 

[Floppy_D]

I didn't mic the case length (just the OAL) but side by side, a 357 necked up and a 40 are nearly indistinguishable. I'm sure I'd hit occaional splits, after I had primed, and they'd all split sooner than 40S&W would, I was just amused by the fact that I found a 357sig round identical to all of my 40 rounds.

 

[AgentAdam]

Maby someone shot a .357sig threw and .40 chamber and fire formed it.

 

[Grump]

I share the amusement factor.

Since the published advice upon the advent of .357 SIG was to NOT try necking down .40s to make it because your cases would be too short....

I'd check the the .357 SIGs upsized to .40 for being too LONG.

'Course, most modern semiautos I've looked at in detail are sooooo loose in the chambering length, you'd be hard-pressed to ever have a case jam in the chamber before the gun's fully locked up.

 

[Crazy Fingers]

I bet it would harden the brass a lot and split the first time you fired it.

 

[Harley Quinn]

Yes they would need to be annealed (I would do it anyway)...The length would be long I am pretty sure... Good thought and read, way to much trouble, unless you are just into learning all the basics of reloading

Regards

 

[ReloaderFred]

I've picked up 357 Sig brass at the range that was fired in a .40 S&W gun. From the primer marks, they looked to have been fired through a Glock.

I've also picked up 9mm rounds fired in .40 S&W guns, and lots of .380 rounds fired in 9x19 guns. I even found a .40 S&W round that had been fired in a .45 acp chamber. On that one, the brass ruptured, and I imagine whoever did it was pretty surprised.

Luckily, I've never been present when any of those rounds were fired, but being an inveterate brass scrounger, any piece of brass I spot gets picked up.

Hope this helps.

Fred

 

[Jayman]

I remember somebody at one of the local ranges talking about getting a custom die to bring .357sig up to .40s&w because a lot of the local agencies trained there, and so .357sig brass was uber plentiful. I never did find out if he got anywhere with that or not...