.357 Sig Shooters / Loaders

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I won't ever load any .357 Sig anyhow, but was just curious, from an "intellectual" standpoint. Your comments about the shoulder being so far back on virgin .357 brass just doesn't make sense. If the shoulder were that far back, you'd have a lot of empty chamber space. The purpose of bumping the shoulder on a fired piece of .357 brass is to return the brass to factory specs. Why would .357 Sig be the only bottleneck on Earth that didn't headspace on the shoulder? It's nonsensical, I tell you! :evil:
 
You are making alot of assumptions. One is that the purpose of resizing is to bring the case back to factory spec. That isn't the case. No sizing die does that. They size the case to chamber in a SAAMI spec chamber. A virgin case will always be smaller than a fired/resized case.

As far as the shoulder issue, go and compare the shoulder position and neck lengths of new and fired/resized .357 Sig cases. It will be obvious.
 
There are actually two datum points on the 357 Sig cartridge, the case mouth and the shoulder. If either of them is too long, the round won't chamber. I've found some cases (Federal) that were too long and had to be trimmed to chamber.

I also found that my first 357 Sig sizing die wouldn't set the shoulder back enough to chamber in my pistols, but instead of taking material off the bottom of the sizing die, I machined off about .005" from a shell holder that I dedicated to this caliber. I figured shell holders are a lot cheaper than sizing dies, and if I messed it up, I wouldn't be out as much. The other consideration was that I did buy the Dillon 357 Sig carbide die set (got a good deal on an auction site) and I wanted to be able to use the shell holder with that die. As it turned out, the shortened shell holder was alse necessary with the Dillon carbide die.

I also chamfer my 357 Sig case mouths and this eliminates the need for flaring the case for bullet seating. I've made a tool for this purpose to chamfer a case, and I can do six cases in about 10 seconds.

It still amazes me that people that don't have any experience with the caliber are full of advice about it. It's easy to tell from the posts who has loaded it and who hasn't..........

Hope this helps.

Fred
 
+1 for HS-6.....found it shoots nicely. It and AA9 are my go to powders for .357 Sig.

After much reading, I decided to spend the $$ for the Dillon carbide die set. After loading several thousand rounds, I'm glad I did.

Although apparently not required, I find lubing the cases makes the process much easier. I also have found that Montana Gold's 125 grain designated Sig bullet works great.
 
Fred, I'm one of those offering opinions on .357 Sig, when I've never reloaded a single round of the stuff. However, I have reloaded over 10,000 .400 Cor-Bons and 3000 .40 Supers. See the connection? ;) I don't believe there's anything unique about .357 Sig, as far as handgun bottlenecks go. Despite authoritative-sounding bloviating, it's still a handgun bottleneck, and the only adjustment one makes, relative to headspace, is bumping the shoulder, just like any other bottleneck. :cool:

Edit: Maybe the SAAMI specs are different for reloaded and new ammo? IF so, that truly is a new one on me. IF the ammo manufacturers don't load to SAAMI specs, then what specs do they use? FWIW, which might not be much, I just measured a reloaded 10mm case and compared it to a factory-fresh 10mm case (both on loaded rounds). Zounds!! They measured exactly the same! I guess this dead horse has just about had enough beating, so I'm moving on to something else. ;)
 
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I have you ever put a new .357 Sig case and a fired/resized .357 Sig case side by side? Have you ever compared the position of the shoulders relative to the base? Be size had you done that you would have immediately noticed the new case shoulder beig some .020" lower than the fired/resized shoulder. You would also have noticed the new case has a longer neck. That should tell you something.
 
hentown,

I've reloaded roughly 14,000 rounds of 357 Sig (no period in front of the 357, since it's a name chosen by Sig), plus I also load for .400 Cor-Bon and 9x25 Dillon. They're all bottleneck handgun rounds. While it's true they can headspace on the shoulder, and some do, if the case neck is too long, they simply won't fit the chamber. That makes them have two datum points, the neck and shoulder. One or the other will work for headspacing, particularly in the 357 Sig, but if they're both too long, they won't work. If one or the other is too long, they won't work. They both have to be within spec. to work, though if one is less than spec., and the other is spec., it will work. I don't know if I made that clear or not...

I size my brass for my chambers, and chambers do vary, depending on the reamer and who chambered it. My two 357 Sig pistols are very close to the same chamber size, so that simplifies things for me in this regard, but one pistol shoots better with 124 grain bullets and the other is more accurate with 115 grain bullets.

The 357 Sig is a flat shooting and inherently accurate round. It's not as flat shooting as the 9x25 Dillon, but is a close second, within about 100 yards or so. The 9x25 gets another 200 fps out of the same bullet, so it's naturally flatter shooting.

Hope this helps.

Fred
 
I understand, the 357 SIG was supposed to be ballistically similar to 357 Magnum when both are using 125 grain bullets and other things being about equal.
Click to expand...

Out of a 4 inch barrel the .357 Magnum is 200fps faster over the .357 SIG and out an even bigger barrel the differences become larger.

Source; BuffaloBore.
 
918v said:
I have you ever put a new .357 Sig case and a fired/resized .357 Sig case side by side? Have you ever compared the position of the shoulders relative to the base? Be size had you done that you would have immediately noticed the new case shoulder beig some .020" lower than the fired/resized shoulder. You would also have noticed the new case has a longer neck. That should tell you something.
Click to expand...
This squares with my experiences/observations as well.

I've NEVER had an issue with my reloade being too long to chamber...quite the opposite if anything.

Want to have some real fun with trying to get enough neck tension? Try forming 40 S&W empties into 357 Sig with an RCBS sizer!
 
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