Loading/Reloading 357 Sig

[Foxbat]

I have a simpler approach that has worked fine in thousands of rounds through several different guns. I take the barrel and start lowering the sizing die, checking for how the sized case goes into chamber. As soon as it falls in freely, and hits the stop with a satisfying cling, I fix the die and never touch it again.

No misfires, no failures to close the slide, just totally consistent behavior.

[peterdaws]

Here in Australia we rushed into reloading for .357 SIG when it was provisionally approved for major calibre in IPSC Standard Division. Government has denied us the use of calibres over .38 for some years now so it gave us a chance to compete again with major calibre standard guns. As a result we now have a couple of years of developing and using the calibre. Nearly all guns so chambered here are on the 1911 platform including Paras, Buls S-Is etc. There are also a smattering of Glocks and Tanfoglios around. As we are also 10 round restricted there are a few that have adopted the calibre for open guns as well, mainly as it gives them compatibility with their standard guns.

Whilst its true that the factory (or SAAMI?) specs specify a case that headspaces on the rim, we nearly all started using resized .40 brass and because that leaves the neck short, we were setting our dies to headsapce on the shoulder. I doubt that many, if any realised, that it was supposed to headspace on the mouth at that stage anyway. Case forming is so effortless that I would just throw .40 cases into the hopper with the already resized ones and there was only slight difference in the pressure required to cycle the press beween the two.

Initially the most used propellent was AP100 which is a slower burning powder in the series that includes Clays, Clays International and Clays Universal. This is the most popular powder used for IPSC Race guns in Australia using 125-130 grain projectiles so was a good starting point. The most common problem we had was that of bullets loose in the case and setting back. The most common fix was the Lee Crimp die that works on the Collet Principle.

Dies are almost universally Lee or Dillon. LEES are readily available and relatively inexpensive. Few have had any problem with them, Some run them dry and others use a lube, mostly Hornady One Shot. The well heeled or Dillon obssesed use Dillon for Dillon for slightly less loading pressue and a smoother finish. Just to be different, I split the difference. I have a Dillon .40 cal die in Stage1 of my 1050 and a LEE sizing Dies in Stage 2, the Primer pocket crimper not being needed.

Very soon we started to use heavier projectiles for the same reason that we did in .40 cal. Up to 145grain ran fine but some tried 165s and 180s. Problems with the projectile yawing or even tumbling started. I am pretty sure that it is because the twist of the rechambered 9mm barrels was too slow. However some believe that it was unsuitable powder or crimping problems.

When I progressed up to 145 grain projectiles using AP100. I was finding that I had unburnt powder grains and velocity spread was a bit erratic. Clearly we were taking AP100 ouside its comfort zone. Attempts to get suitable major loads (170p.f.+) with AP70 (Clays Universal) were pushing the envelope. I also had several misfeeds where the slide didn't quite go into battery. I experienced it several times in matches and cylcled the action to finish the stage so I could never determine the cause. When one day it happened on the rare occasion I was practicing, I carefully unloaded the gun and took it off line and stripped it. There was a single powder grain sitting on the shoulder of the chamber!. So I changed to Power Pistol worked up to a nice load with the 145 grain projectile and my problem disappered. The only concern was that the imported powders tend to have an unreliable supply chain and the laws here limit the amount we can hoard.

From this experience, I wonder if .357SIG, having been designed essentially as a service round was designed to headspace on the mouth so that there can be a slight clearance bewtwen case and chamber shoulders?

Recently one of our bullet makers came out with a 170 grain projectile without a lube groove. (Coated cast lead projectiles are almost universally used here) I think because its shorter than conventional lube grooved projectiles I have seen no instability problems with it. Better yet AP70 (Clays Universal) seems to be just perfect for it. I havn't Ransom Rested my loads but loaded to 174-178p.f. I am getting very low velocity spread and single digit Standard Deviation. Loaded out to 1.25" for my Bul M5 it has proven 100% reliable so far.

After a two year search I think I may have found the Holy Grail in SIG loads for Standard Division.

Peter

[Macca]

Peter,

What projectiles/load are you running, although I will be loading for a sig, the concept of the holy Grail of loads is appealing.

I've been looking at possibly selecting a hrbc or Topscore 9mm/38 super projie, but I noticed westcasting actually lists a flat point for 357sig?

Any info would be great........I've settled on AP70N as the powder anyway as I have a few large bottles on hand as is.

Thanks.....

[FJTIbbetts]

After reading the above postings, I took 10 Federal 40S&W cases and necked them down to 357SIG. They were approximately .010" to .015" shorter than my 357SIG Speer Nickle Plated Brass. I loaded them up at an COAL of 1.140", 7.4gr Power Pistol and 125gr Montana Gold FMJ.

Went to the range and fired them with no failures. Just as accurate as the 357SIG brass.

There is mention in the posts that the 357SIG spaces off the case mouth. From my experience it spaces off the case shoulder. I took both pieces of brass and checked them in three different barrels (XD, Glock & KKM) and there was only .002" difference. The .002" difference must of been how I set my sizing die.

For whats it is worth, this is my experience.