Converting .357sig to .40 s&w

[.40AET]

I got a .357 sig case in a batch of .40's the other day while reloading. The powder funnel seems to have resized it out to .40 dimensions. After seating the bullet, the brass looks pretty bad. Would you keep these and use them for practice, or consider them too dangerous to shoot and chuck 'em out? I'm not looking to resize thousands of these, just the occasional one that sneeks into the machine.

Thanks in advance,

Kirk

[dirtypool40]

I dunno, didn't they originally start life as a .40 necked down?

I've had them sneak in there too, and always stopped and trqashed them.

If you live through it, tell us about the experience.

[Guy Neill]

The 357 SIG case is longer than a standard 40 case by about 0.015". Best not to use them as a 40 unless they were trimmed. Even then ,there are enough 40 cases avaialble for low cost it wouldn't be worth the bother.

Guy

[Larry White]

Chunk em, brass is cheap and you will have a problem at a bad time. Larry

[.40AET]

I was also under the impression that .357sig is a necked down .40. And yes, brass is almost free. I have 2 rounds sitting on my bench, and I don't want to try to live through the experience. I was hoping that someone else may let me in on the results. I'm pulling the bullets and chucking the brass/primers if the thread keeps going in this direction.

[blkbrd]

Much to my chagrin I sometimes get a 357 Sig case mixed in with my 40's complements of the Airmarshals.

I have expanded 2 of them, and neither of them would I trust for a reload, the necks had tiny cracks and buckles from resizing.

Have learned to hate the caliber and don't understand the Airmarshals using them. And for the record, none I have talked with like them either and would have prefered 40's instead.

[warpspeed]

I had a handfull of them in a batch of 40 once. Decided to load them just to see what happens, if anything. Loaded rounds passed case guage so out to the range they went.

Load was 180 gr jhp over VV N320 - 170 pf load out of an STI. Did not check them for accuracy, only function. Ran through a mag of 20 without a hitch. I picked up brass and did not have any splits or cracks. Brass went into recycle pile.

There is no problem shooting them if they get mixed in but since they are easy to sort out due to the extra force needed to expand them, you should cull them.

[BLISH LOCK]

i have sized a few 357sig open to 40. and reloaded them for a steel match

they all shot fine , didnt pick up the brass

loaded to 160 p.f. and function fired a hand full before match

[Flexmoney]

Risk vs. Reward!?

Why take any chance...whatsoever...with these?

[JFD]

I agree with Flexmoney on this. With .40 brass nearly free, what could possibly motivate someone to try and convert .357 sig brass?

Throw the stuff out and remember that there can be awful consequences for situations where the careless handloader is "just wondering if it will work".

[.40AET]

Thanks a lot for all of the input. The f***ing things keep sneaking into my press. I check my brass twice before tossing it into the casefeeder. I have never shot the two that I made and will throw them and the rest away as they show up. There is no reward in converting the rounds, and the risk is high. I kinda lost the tread until it just popped back up. Thanks for the sound advice.

[Duane Thomas]

I was also under the impression that .357sig is a necked down .40.

In concept, yes. And early experimental .357 SIG cases were indeed made by necking down .40 S&W. But what they found was that if they did that, the case neck wasn't "tall" enough to grip the bullet hard enough, and they had problems with bullets setting back into the casing during feeding. Bad news. In order to solve that problem, they made the case neck longer in .357 SIG casings than it would be if it were simply .40 necked down.

[a-44978]

Kaaboom?Maybe me thinks.

A while back i went on and on about how this is no problem,but..........

Last week i blew up 2 G22s at a match.

Not sure if they were .357 casses or not because the entire bottom was gone along with the extractor and a couple of other parts.

My Dillon has passed the 50k mark with me and my glocks without a problem like this.

I can only hope this is the problem.I hope the resizing process stressed the rim too much.I have pulled about 40 or so bullets from this last batch(some were .357) and rechecked my powder.I'm now loading a MG 165g FMJHP with 5.3g hogdon clays @ 1.125 oal,with a high of 5.5 and a low of 5.1.

I got a class coming at the end of summer(2500 rounds) so i hope not to buy casses of cci or whatever.

Bottom line is NOT WORTH IT

I would gladly give the .50 cents i saved on brass not to replay last Sunday.

[short_round]

300lb Gorilla had some .40 reloads that were made with .357 sig brass ... at least that's what was on the head stamp. They seemed to work fine. It's difficult to say really, it was Cullen shooting them after all.

[kimel]

I shoot fairly regularly with a guy from Canada who runs a .357 Sig Open gun and he uses .40 brass necked down for all his ammo. He has zero problems with it. I am not sure if he had a custom made barrel or not.

[MikeFoley]

All interesting reading, but another one of those places you just shouldn't go. I agree with Flex. It only takes one for you to report other findings that will not be so pleasant.

[.40AET]

Hey guys, a year later and this pops back up.

I have a big can full of .357 sig cases.

Cheers!

[Tman33_99]

357 Sig is also thicker than 40. Even though the case diminsions are the same, the Sig round is designed for higher pressures than the 40. Ship your Sig cases to me and I will dispose of them properly.

[Harmon]

Kaaboom?Maybe me thinks.

A while back i went on and on about how this is no problem,but..........

Last week i blew up 2 G22s at a match.

Not sure if they were .357 casses or not because the entire bottom was gone along with the extractor and a couple of other parts.

My Dillon has passed the 50k mark with me and my glocks without a problem like this.

I can only hope this is the problem.I hope the resizing process stressed the rim too much.I have pulled about 40 or so bullets from this last batch(some were .357) and rechecked my powder.I'm now loading a MG 165g FMJHP with 5.3g hogdon clays @ 1.125 oal,with a high of 5.5 and a low of 5.1.

I got a class coming at the end of summer(2500 rounds) so i hope not to buy casses of cci or whatever.

Bottom line is NOT WORTH IT

I would gladly give the .50 cents i saved on brass not to replay last Sunday.

<{POST_SNAPBACK}>

5.3 grains of clays , or universal clays??

accidently necked up .357 sig brass wouldnt chamber in my gun(too long)

not sure how a case neck failure could cause a KB, normally its the case HEAD that does that...and in that respect, the .357 sig brass is better than the 40..

[a-44978]

Kaaboom?Maybe me thinks.

A while back i went on and on about how this is no problem,but..........

Last week i blew up 2 G22s at a match.

Not sure if they were .357 casses or not because the entire bottom was gone along with the extractor and a couple of other parts.

My Dillon has passed the 50k mark with me and my glocks without a problem like this.

I can only hope this is the problem.I hope the resizing process stressed the rim too much.I have pulled about 40 or so bullets from this last batch(some were .357) and rechecked my powder.I'm now loading a MG 165g FMJHP with 5.3g hogdon clays @ 1.125 oal,with a high of 5.5 and a low of 5.1.

I got a class coming at the end of summer(2500 rounds) so i hope not to buy casses of cci or whatever.

Bottom line is NOT WORTH IT

I would gladly give the .50 cents i saved on brass not to replay last Sunday.

<{POST_SNAPBACK}>

5.3 grains of clays , or universal clays??

accidently necked up .357 sig brass wouldnt chamber in my gun(too long)

not sure how a case neck failure could cause a KB, normally its the case HEAD that does that...and in that respect, the .357 sig brass is better than the 40..

<{POST_SNAPBACK}>

[a-44978]

Kaaboom?Maybe me thinks.

A while back i went on and on about how this is no problem,but..........

Last week i blew up 2 G22s at a match.

Not sure if they were .357 casses or not because the entire bottom was gone along with the extractor and a couple of other parts.

My Dillon has passed the 50k mark with me and my glocks without a problem like this.

I can only hope this is the problem.I hope the resizing process stressed the rim too much.I have pulled about 40 or so bullets from this last batch(some were .357) and rechecked my powder.I'm now loading a MG 165g FMJHP with 5.3g hogdon clays @ 1.125 oal,with a high of 5.5 and a low of 5.1.

I got a class coming at the end of summer(2500 rounds) so i hope not to buy casses of cci or whatever.

Bottom line is NOT WORTH IT

I would gladly give the .50 cents i saved on brass not to replay last Sunday.

<{POST_SNAPBACK}>

5.3 grains of clays , or universal clays??

accidently necked up .357 sig brass wouldnt chamber in my gun(too long)

not sure how a case neck failure could cause a KB, normally its the case HEAD that does that...and in that respect, the .357 sig brass is better than the 40..

<{POST_SNAPBACK}>

[a-44978]

Ok

Now i can type........................

Yes case head failure,case did not split,bottom blew off.Twice in 50 or so rounds

Hogdon clays.

I shot about 200 rounds through my STI today at 1.185 oal

AND a correction I'm shooting a 155g FMJHP MG not 165g.

After 3 or 4 years now i still feel green as the grass grows

Now the question is .............Is there a big difference between Hogdon clays and universal clays?

Could i have done my chrono testing using one then later loading the other?

My goal was to find a load that i could use for both my Glocks and my STI while only changing OAL.

Back to the drawing board i guess, and a different theadmaybe too

Thanks

[High Lord Gomer]

I could only find the occasional reference to resizing .40 to .357 Sig. Even though this thread started off talking about going the other direction with the brass, it seemed closer to what I need than the others...

A fair number of the .357 Sig cases I have found while sorting brass are actually marked "40 S&W", so apparently there are people doing this fairly regularly. I have a TON of .40 brass and am getting ready to start doing .357 Sig. Of the poeple who resize .40s down to .357 Sig, have you ever had any problems with bullet setback? Do you crimp more than usual to prevent it?

[Alan550]

I tried it in my glock and the cases were too short after necking them down. Not enough length left to hold the bullets firmly without a hell of a crimp which deformed the case too badly to chamber.

Factory specs say that case length is .865" for the SIG round and only .850" for the .40. If you neck down a case that's shorter to start with, it gets even shorter with the shoulder put on it, leaving not enough neck to hold the bullet.

YMMV

Alan~^~

[wide45]

oops... tried to reply to a 4 year old post.

Edited December 4, 2009 by wide45