View Full Version : reloading the 357 SIG
Boolseye
05-07-2016, 04:47 PM
I'm starting this thread as a catch-all for the basics on this cartridge.
I learned everything I needed here at the forum, but there is a shortage of info.
The primary challenge in reloading for .357 SIG is getting through the neck tension issues and finding good boolits. The bottleneck only has about 3/16" that grip on the boolit, so a boolit with enough of a top driving band, and a short enough nose for the mags is a necessity. Examples of boolits that I have used thus far: Lee 356-120 TC (standard groove), Lee 358-158 RF, Accurate 35-147S. Many folks rely on a full case of slow powder to act as a stop for the boolit, and to ensure that set-back doesn't happen. I prefer to also give each round a good crimp.
Boolits that have been known to work are:
Lee 358-125 RF
Lee TL356-95RF
Lee 358-105 SWC
NOE 357-135RF (Ranch Dog)
Accurate 35-125S (357 SIG nose length)
Accurate 35-147S (" ")
Jax:
Hornady XTP HP 124 and 147
Traditional long-nose 9mm boolits such as NOE's 358-135 RF/128 HP) will likely not function well.
too little upper driving band, too long a nose.
Lets hear from ya 357sig shooters!
lightload
05-07-2016, 05:03 PM
Lee makes a factory crimp (collet)die for .357 Sig. Others have pointed out that a 40 S&W carbide die works for sizing the case section below the neck.
awhite
09-02-2017, 04:10 PM
Any suggestions for 125 bullet loads? I have Unique, Bullseye and Power Pistol. I'm loading for an H&K VP 40 with a .357 Sig barrel which slugs at .357.
Thank you.
dansedgli
09-02-2017, 05:49 PM
Accurate 168z and mihec 135 grain work well too.
Moonie
09-02-2017, 10:12 PM
I'm using the Lee 125 FP, size with 40 S&W then 357Sig crimping with the collet FCD. Working perfectly with around 7gr of Unique or around 9gr of AA#7.
Beef15
09-03-2017, 09:13 AM
Any suggestions for 125 bullet loads? I have Unique, Bullseye and Power Pistol. I'm loading for an H&K VP 40 with a .357 Sig barrel which slugs at .357.
Thank you.
I would use the Power Pistol. I had good results with the Lee 120TC and that powder, don't remember the charge.
What will likely be a challenge for you is expanding the neck for and/or seating a fat enough cast bullet without collapsing the shoulder, I have for the time abandoned cast in my 357Sig due to losing 1/10 or more. Perhaps someone can offer a solution?
Boolseye
09-03-2017, 12:08 PM
I have not had any shoulder collapse issues-as I recall I just used a Lyman m-die and gave the mouth a flare. I drop my powder charge then seat as normal with a strong crimp, done as a separate stage. I may have used the Lee universal expander to flare, I can't recall. Expansion of that little neck is important or you will shave lead and possibly crush a shoulder. Just going from memory, it's been a while.
dragon813gt
09-03-2017, 01:33 PM
What will likely be a challenge for you is expanding the neck for and/or seating a fat enough cast bullet without collapsing the shoulder, I have for the time abandoned cast in my 357Sig due to losing 1/10 or more. Perhaps someone can offer a solution?
Use a proper expander. I've never experienced any shoulder collapse issues. As stated neck tension is usually the biggest issue. W/ the Lee short bottle neck collet style FCD that's no longer an issue either.
Boolseye
09-06-2017, 07:11 PM
Update: The NOE 358-150 ELKO design works well in this cartridge. It's a great choice for a heavy. I believe I went with 6.5 gr. 800x and got about 1000fps.
This load was very low and could be kicked up if the shooter needed more power.
How are you getting the Elco to seat at 1.140" COAL with any neck tension.
bstone5
09-09-2017, 01:18 AM
The Accurate 35-120G also woks well in the 357 SIG. I size to 357 after powder coating then a home made gas check is installed. Have shot many in a 375 SIG. Use the Lee crimp die for a small crimp so as not to damage the powder coat material on the cast bullet.
Use the same bullet in 38 Special with 3 grains of Trail Boss for the ladies and grand children to shoot in revolvers.
Boolseye
09-09-2017, 02:07 PM
How are you getting the Elco to seat at 1.140" COAL with any neck tension.
I don't recall the exact OAL, I think I did 1.145". It worked great in my M&P.
Neck tension was fine too. I do use a strong taper crimp on .357 SIG, using the Lee fcd.
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