Reloading the .357 Sig

[garandman]

I am in need of a good recipe for the .357 sig using Unique powder. I was at a local gun store that was closing and picked up a couple pounds of Unique and 300 rounds of Winchester 124 gr. FMJ that was heavily discounted. I didn't find out until later that I can't find a recipe for the two? I am relatively new to reloading and only have the Lee handbook. I looked on the Alliant powder website, but they only have a listing for 125 gr. Speer GDHP. I already have the dies and plan on using the factory crimp die to try and reduce set-back.

I also have some HP38 on hand, but it doesn't appear to be a good match.

 

[DickM]

The 1 gr difference between the two bullets is not significant. What can be important is the potential difference in the bearing surface and the thickness of the jacket. I know the .357 SIG can be finicky (I load for it as well), but you should be fine using the starting load for the Speer bullet and working up carefully (or not at all, depending on what you plan to use the load for).

 

[loadedround]

The current Speer #14 Manual shows a loading for the 357 Sig with Unique and 125 gr jacketed bullets that you many use for your 124 gr bullets:
Starting load: 7.2 gr
Maximum load: 8.0 gr
You may also want to check Hodgdon's reloading site at www.hodgdon.com for additiol loads for your 357 Sig pistol.

 

[pete950]

When our agency went to this round I was talking to the Speer LE rep who told me the factory duplication at that time was 7.0 of bullsey. When I was reloading that cal I used 6.7 of Bullsey and every one who shot stated that that load was dead accurate. The bullet I used was the Rainer 124 flat nose .355 Good luck

Pete

 

[ATAShooter]

I used to load 357sig with unique, bullseye, and green dot. Green dot rounds have alot of snap to them.

 

[five.five-six]

just got a 229 in .357sig I need to start working up a load, I have pounds of bullseye, so I would like to use that. my bigest problem is that I am having a hard time tracking down my brass, it seems to go in every direction. can I form it from .40S&W like a .400Cor-Bon from .45ACP?

 

[skipjack]

I load Longshot with Hornady XTP bullets, the data is on Hodgdon's reloading
data center website. I have also used Hornady HAP bullets as a cheaper
substitute for the XTP. Longshot meters well through my Dillon 650, and the rounds are pretty snappy.

 

[five.five-six]

can I make .357 sig brass with 40S&W the same way you make .400 corbon out of .45ACP?

 

[JimKirk]

I would not ...357 SIG brass is made for 40,000 PSI, 40 S&W is for 35,000 PSI.

The 357 SIG case is stronger to withstand the higher pressures.

Also the neck would be a 1/10 of and inch shorter than the 357 SIG neck which is almost too short as it is.

Jimmy K

 

[snuffy]

can I make .357 sig brass with 40S&W the same way you make .400 corbon out of .45ACP?

I say no. The reason I say no is, the resulting case is shorter. Just how much I don't know for sure, IIRC it's about .020 shorter in the neck area. The 357 sig has such a short neck as it is, making it shorter is NOT what you want to do. 357 is a name, not a caliber designation like .357 would be. It's actually .355 diameter. It got it's name by the fact that it can drive a 125 grain bullet out of a high capacity semi auto at the same velocity as a 4 inch .357 magnum revolver.

You HAVE to use a TC bullet, truncated cone. It should be .355. Do NOT use a round nosed 9mm bullet, in order to feed through a mag, it has to be seated too deep to get a crimp on the full caliber side of the bullet.

Neck tension is very important. If the neck tension is tight enough, you don't really need a crimp. I do use a lee FCD, which is a collet die like the bottle neck rifle dies. Just to be sure to prevent the bullet from being set back during chambering. Another reason NOT to form cases from 40 S&W, shorter neck = less neck tension.

As for loads, I use power pistol or AA#9. I prefer the slower powders for this round. I'm firing these from a KKM after market barrel in a Glock M-22. Nice thing is, a simple barrel swap, and you get to use your 40 mags!

 

[five.five-six]

ok, good advice... I made 10 rounds with 40S&W... I will probably just pull the bullets. they did measure 15 thousandths short. I was going to use plated RN 9mm bullets but like you said, they seated too deep, it's a tricky crimp to get them to stay put and i am concerned about huge overpressure from to much projectile in the casing. the only FN .355 125 bullets I have are hard cast lead... I am working up a load with those (I don't know why as i am going to be loading this with jacketed) starting with 5.8 grains bullseys, 6.0, 6.2, 6.4 and 6.6 grains


where to find 124 grain FN or SWC jacketed bullets in bulk?

 

[dc.fireman]

and, Welcome to The High Road!

 

[JimKirk]

http://www.shop.rmrbullets.com/product.sc?productId=19&categoryId=12

Jimmy K

 

[ArchAngelCD]

As said above, there's no reason not to use the load data on the Alliant site just because there is a 1gr difference in bullets. They list a Max charge of 8.0gr so drop back 10% and work up. As for HP-38 I agree, it's really not a good fit with the .357 Sig...

Welcome to the forum and reloading...

 

[five.five-six]

so i made 50 rounds with 124 grain hard cast Lead SWC starting with 5.8 grains of bullseye 10 each in 2 grain increments, the results were horrible, the remaining 35 are going to the kinetic puller.

first off I only shot 5 of each load, most all the rounds keyholed, I read that these need to be loaded more like rifle rounds, and i am thinking the SWC left too much "jump"


2ndly, at 4.6 grains (do not exceed was 7.0) I was blowing primers, again I suspect the SWC was leaving too much bullet in the case to keep my OAL fitting in the magazine, giving me overpressure big time


next step is to buy 100 each rainier plated FN and hornaday jacketed FN 124s and see which I like i hope it's the rainier because they are about 9 cents each @3k

 

[five.five-six]

I'm thinking that bullseye is not all that good of a choice for .357 sig... if I am going to buy a powder solely for this round, what should it be?

 

[ArchAngelCD]

I'm thinking that bullseye is not all that good of a choice for .357 sig... if I am going to buy a powder solely for this round, what should it be?

We all agreed above HP-38 was a poor choice for the .357 Sig so why would you use Bullseye which is even faster?

If I were going to buy a powder specifically for the .357 Sig it would be Hodgdon Longshot. IMO it will work best.

 

[JimKirk]

I load for the 357 SIG... I've had good results with HS6. The reason I'm using HS6(Win 540) is because I have a big jug left over from shooting 20 ga shotshells. I've mostly been loading Hornady 124 gr XTP with the HS6, it is fairly fast with good accuracy and clean burning. I'm working with some left over IMR 800X, I'll give a better report on it later.

Jimmy K

 

[243winxb]

357 Sig

http://www.thehighroad.org/showthread.php?t=410358 Have fun reading. Has photos also.

 

[ArchAngelCD]

Even though I suggested Longshot I have to agree with Jim, HS-6 is also a good choice. Both powders are of similar burn rate but I usually use HS-6 more for lead bullets than jacketed. Nothing wrong with HS-6 in the .357 Sig.