Handloading the .357 Sig

misterarman · Jul 9, 2015

Curious how many people shoot and reload for this caliber?
Hardest caliber to dial in I ever experienced. Easy in the sloppy Glock barrels but as soon as I tried an aftermarket "match grade" barrel the fun began. Then I learned about camming over when resizing and I was back in the game.
Anybody just use the RCBS 2 die set or the 3 die Dillon or Hornady sets?

Also interested in what powder and bullets are being used?
I started with the Hornady 9mm HP/XTP 115gr then 9mm 124gr then the Montana Gold 9mm 115gr JHP then their 9mm 124gr JHP then their 125gr JHP .357sig bullet.

I started out with Accurate Arms #7 and when I ran out I tried AA#5 and even though the data in the manual was close did not care for it. So I went back to AA#7. Heard good stuff about using AA#9 and am in the process of checking it out.

Anybody neck down 40 s&w cases to make 357sig?
I started out doing that and it was probably 95% effective. I would never stake my life on it. New opinion says not to do it because they come up short in the neck which is fairly short to begin with. That being said I found an older set of RCBS dies that had a tag in it explaining how to do it.
I have since been using actual .357sig brass and am much happier with the results.

ReloaderFred · Jul 9, 2015

There have been a lot of threads on the 357 Sig (no period before the number, since it's just a name). If you do a search, you can bring up all kinds of information.

Here's one to get you started:

http://www.thehighroad.org/showthread.php?t=678131&highlight=Loading+357+Sig

Hope this helps.

Fred

vaalpens · Jul 9, 2015

I shoot and reload 357sig and reloading it definitely keeps you on your toes.

I have tried a few bullets and have settled on the MG 125gr 357sig JHP bullets. I have not tried the MG 125gr 357sig FMJ (flat point) bullet yet, but see no reason why it won't be as good as the JHP.

I also load plated bullets, but I load them towards the low end. The bullets I use are the RMR 124gr match plated flat nose bullets and the Berry's 124gr HBFPTP bullets which are both .356" diameter. I only load these with Unique and they are great for practice and plinking.

The dies I use are the Lee 3 die set + the Lee FCD. This has been working for me. In addition to the 357sig dies I also use my 40S&W dies to resize the body and the 40S&W Lee FCD to debulge the cases. My process is; lube/debulge with 40 FCD, resize with 40 die, resize neck with 357sig die.

The powders I currently load are Unique, Longshot and Power Pistol. I tried to stick to powders I can also use in 9mm and 40S&W. I have never tried the AA powders since I can't find them locally yet. My next powder I would like to try will probably be BE-86.

I have necked down some 40S&W brass and tested them for setback with dummy rounds, which they passed, but I have not loaded any 40S&W brass yet in 357sig.

Working with 357sig has become easier and I now sort my brass based on length. It is more work but it helps to get the flaring consistent and kept to a minimum, which again helps with neck tension.

I try to keep the 357sig in the family and shoot it through my P229.

Good luck with the reloading and be safe.

TfflHndn · Jul 9, 2015

If you think 357 SIG is a PITA to load, don't buy a 22TCM!

AA#7 and AA#9 are good powders for 357 SIG. I have used a fair amount of Blue Dot in it also. Recently tried some HS-6 with very good results. I generally use Montana Gold 125 bullets, and I like them a lot. I don't have to worry about pushing them too fast like plated. I use the Hornady die set for neck sizing, flaring and seating, after an RCBS carbide .40S&W die for body sizing, and finish with a Lee FCD. Sizing with the carbide .40 die is much easier than using lube.

vaalpens · Jul 9, 2015

You made an interesting statement regarding using 40s&w brass.

misterarman said:
I started out doing that and it was probably 95% effective.

What do you mean by 95% effective? Does it mean 5% missed the target, or 5% did not go bang, or 5% went Kaboom, or 5% could not be sized properly?

misterarman · Jul 9, 2015

I started with an RCBS 2 die set and that didn't make sense so I used an extra 9mm expander die and even with cam over the case did not come out as good as with the Dillon carbide sizing die. Hated springing for the Dillon carbide but a friend showed me the diffrence and it doesn’t even look like the same caliber.
According to the guys at Dillon even doing the 40 sizer and the carbide 357 sig sizer with no lube eventually you will get a case stuck.
I'm really glad to hear all positive results with AA#9 and I'm going to do my 1st batch at the range in the mornimg.

misterarman · Jul 9, 2015

The 95% effective was in regards to bullet setback.
After measuring it seems the neck comes up short and causes crimping problems

dnfd737 · Jul 9, 2015

years ago when I ran 38 super a lot I built a double stack para in 347 sig....I made brass from 40 cal it was a complete pain I was thinking I could get an advantage on the 38 super for shooting idpa and uspsa ipsc ect.....well not so much, I loaded 130 gr? maybe 135 gr? with aa#2 at max 1450 fps and down loaded to 1100 fps for matches....just enough to make required power factor....I found in the end the 38 super was easier and more reliable, I did anneal the brass when sizing 40 cal to 357 sig.....plus 357 sig is very loud I think 400 corbon is a better way to go......many people frownd upon aa#2 as it had a short starting to max load as per the books, but I load well past the max with no signs of over pressure

misterarman · Jul 10, 2015

Aw, the bottleneck cartridge. I definitely have a thing for 9MM so the .357sig is just an extension of that. Plus it gives me a way to use my G22 because it doesn't get used for 40. I'm not going to start that debate cause I don't think there is anything wrong with the 40 I just like 9mm better and I also like 45acp better than 40 so I don't end up shooting 40 and would probably not go down that road if I had it to do over.
I also like the bottleneck cartridge theory for more feeding reliability. Plus it's a little different. It doesn't hurt that the 357sig makes a magnum 9 although I don't feel underprotected with a standard 9mm. For the cost of a barrel you get a new caliber to play around with.
The .400 CorBon is my latest adventure. I have not been able to a lot of data for it so if you would like to share some I would sure appreciate it. I have shot 155grjhps in 40 and 180s in 10mm but am thinking I may want to try 165s for the .400? Started out with the 180s. Also started out necking down 45acp brass and been more satisfied with it than necking down 40 for 357sig. Now have some actual 400 CorBon brass and have it prepped and ready to go have not loaded any.
Not planning on doing the competition shooting thing but do like my guns to perform well.

Handloading the .357 Sig

misterarman

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ReloaderFred

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vaalpens

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TfflHndn

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vaalpens

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misterarman

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