Tips and cautions for loading .357 SIG

[kcofohio]

Speer brass has small flash holes also. So far the Lee sizing die decapping pin, it is small also, has done well.

 

[Lennyjoe]

I have a couple hundred a Starline brass en-route

 

[Chillydog]

I size this round to headspace on the shoulder, just like a bottleneck rifle. Specs will say the case mouth but that is not my experience. I don’t see any point in pushing the shoulder back further than necessary.

ymmv.

 

[JimKirk]

I size this round to headspace on the shoulder, just like a bottleneck rifle. Specs will say the case mouth but that is not my experience. I don’t see any point in pushing the shoulder back further than necessary.

ymmv.

I pull the barrel out of the gun and use that as "the gauge" .... I size to headspace off the shoulder also... If I set my dies as the instructions say ... it sets the shoulder back too much.

 

[packetloss]

I suspect the confusion and misleading instructions on this is because it can headspace off both. For factory rounds they are headspacing off the mouth. Once fired, if you set your dies up for maximum longevity of the cases, it would be on the shoulder. But it will work if you push the shoulder back too much and let it headspace off the mouth. You just won't get as many reloads out of the cases.

 

[Lennyjoe]

Looks like I’ll be stepping up reloading this caliber. In addition to converting the G27 to 33 with aftermarket barrel, I picked up a G32 with the following extras for $680.

Lightly used G32. Less than 500 rds through this. Comes with: Trijicon Night Sights (installed) Original Glock Sights 7 magazines (3x .357sig, 3x 9mm, 1x .40 s&w) Custom Pelican Storm Case Glock .40 s&w barrel Lonewolf AlphaWolf 9mm barrel. Lonewolf stainless recoil spring assembly Original recoil spring assembly All original parts and box. Ambidextrous BladeTech AIWB holster.

Won’t have much need for the 9MM and .40 barrels but since I have a G19 the extra 9mm mags will come in handy.

 

[vaalpens]

Welcome to the 357sig world. I actually tested a few loads last week, but haven't posted my results yet.

Setback is definitely an issue, so my suggestion is to load a few dummy rounds and test for setback. My setback test is cycling the dummy round manually through the gun 5 times, and then finish it off with a bathroom scale test. There is normally a bit of setback, but if it is minimal, then you are good to go. You still have to do your plunk test to ensure the rounds fits your barrell.

My process is:
1) Clean cases
2) Debulge with a Leed .40 FCD (internals removed) push through. A little bit of case lube works well
3) Resize with Lee 357sig die. Should still be enough lube from the debulge
4) Clean to remove lube
5) I sort by case length so that I can load by case length. It gives me a bit more control over the amount of belling/expansion. Keep it to a minimum
6) Prime, expand, powder. Using the Lee expander die.
7) Lee seating die
8) Lee 357sig FCD.

I adjust the expansion die and Lee FCD every time for a different case length.

I had some Starline cases before and had a tough time making them fit my barrel, and even setback issues. These case were put aside until I started using the debulger, and now the Starline cases are also in the rotation. The debulger is a bit more effort, but I think it does a great job.

I have never used AA#9, but it should be good. All these work well: BE86, Unique, Longshot, Power Pistol, CFE Pistol. Lately I have been loading with W244, which gave me very good accuracy at around 1300fps.

RMR makes some good bullets for 357sig, but there are some other excellent bullets also. One of the is definitely Montana Gold 125 grain .355 JHP bullets.

Good luck an be safe.

 

[Lennyjoe]

Hornady dies arrived along with a Wilson case gauge, Starline brass, 160 mixed once fired brass, 500 Montana Gold 125 grain .355 JHP bullets. Also have a pass they .40 cal die coming since some of the once fired brass appears to have been shot out of a Glock.

Instead of trying to set up my Lee Loadmaster for sizing I’m gonna run the once fired thru the pass thru die then size with the Hornady on a single stage press. I have it set up to headspace on the shoulder, verified with the Wilson gauge. Will finish the case prep with a minor chamfer instead of belling the mouth for now.

Will powder charge, bullet seat then factory crimp on the Loadmaster.

As for powders, I have BE 86 and AA9 to try first.

Finally, I have the following ammo for personal defense and will see which groups better for my PP choice.

 

[WrongHanded]

Finally, I have the following ammo for personal defense and will see which groups better for my PP choice.

View attachment 936638

Both excellent choices in my opinion.

 

[george d dennis]

I use starline brass, AA#9 .Nosler 124gr. with a lee crimper. works great in my Glock 31 and 33

 

[Lennyjoe]

Federal seemed to group a little better than the Gold Dots. Also tried some AA#9 with the Montana Gold 125 gr JHP. Indoor at 15 yards. First time shooting this caliber. Still some work to do to bring in the groups a little more. Speer 13th edition shows 14.6 grains as max with a 125 grain GDHP but I’m not sure I need to go that high. I used Accurates data and stopped at 13 grains which is their listed max.

BTW, I know my target choice is for rifle but I have a ton of them and like to aim small for pistol....lol