Of all the brass sold and load data I never see anything about the SIG.

Is the neck too short to make it a normal proposition.

I have done so.

I just don’t shoot enough of it that I have recently.

My deceased shooting partner uncle loved the round, and I’ve probably loaded 2-3000 rounds of it lifetime.

Set up of the dies is a bit picky compared to most other handgun rounds. I tend to put a fair amount of crimp on them due to the design.

I’ve never felt the need to push the performance envelope with it. I’ve also got a 9x25 Dillon that makes the SIG round look anemic.

Good article by Brian Pierce in Oct 2021/#334 Handloader Mag.

I have been reloading the .357 Sig for a long time. Bullet selection and neck tension/crimp can be a bit tricky but loading it isn't particularly difficult. I shoot a lot of cast bullets in mine.
C.G.B.

I've loaded & use a .357 Sig Sig for 20 years. It was the original duty gun of my daughter in the VA State Police. I bought one to match hers.
I've taken 20+ groundhogs with it and 5 deer using mostly Speer Gold Dot bullets , handloaded.
To help her out I bought a mini Glock (Mod. 33?) for a backup. I tested it out, killing a dozen groundhogs out to 40 yds. Both guns are reasonably accurate and not difficult to shoot.
Lik3 CBG said, neck tension is a little tricky (less is better).
It didn't perform great on deer- all ran a ways,but it works. I've only use Unique in my handloads. Never any problems.

Thanks to one and all.
One sees posts about most other cartridges, but little on loading the SIG round.

What little I have shot one it was great on pop-up silhouette targets to WAY out there.

Not bullseye, but hits

It's just like reloading a bottleneck rifle case. Easier than straight wall cases, you don't have to worry about case OAL, you can chamfer the inside of the case neck for easy bullet seating without a neck expander die. And you can use a standard crimp if you desire.

The neck is short so short, light bullets work best.

I was using 115 jacketed bullets and 9 grs of Power Pistol. Alliant at one time listed 10 as max but I think that's too hot.

I've been casting/loading/shooting the 357SIG thru SIG P 226/229 series pistols for 30+ years.

Projectile ogive is critical to avoid bullet set back upon feeding.

Accurate/Accurate Arms #9 will push .355" 125gr L R FN to 1450fps easily....verified by Oehler 35P chrony.