.357 Sig Shooters / Loaders

I load and shoot 357 SIG. It reloads just like any other pistol round, really. You will need to buy some true jacketed bullets for it to work at full power. The bullets need to be 9mm JHP or flat nose. I like nosler 124 JHPs for full power.

Setback is a commonly discussed issue, but picking an appropriate bullet and using AA #9 powder will prevent it.

I would compare the recoil to a 40 in fast forward. The recoil impulse is over very quickly, but there is a lot of blast and depending on powder, a lot of flash too.

Ballistics are similar to a standard load 125 grain 357 magnum out of a short barreled revolver. You'll likely see velocities around 1380-1400 FPS with 124 grain bullets. You can get similar performance from +p+ 9mm, but it stresses the gun. The 357 SIG pistols were designed for it. That's what makes it NOT redundant.

IF you properly spring the 9mm pistol, then how would it be stressed any more with +p+ than a .357 Sig would be shooting .357 Sig? The Glock 9mm frames are the same as the .40/.357 Sig frames.

Is there any particular process you have to follow to reload .357 Sig?

I've read different places that some folks use a 40 S&W resizing die to do the initial resizing, then a .357 Sig resizer to do the neck.

Also, some folks use a bullet seating die to set the OAL and then another die to crimp.

Are all of these extra steps necessary?

It all depends on the die set you've got! If you have the Dillon carbide set, you can just run them through like all the other calibers. If not, then you either have to lube them before resizing, or do the 2-step process that you described with 40 S&W die and the .357sig resizer.

I use the 2-step resize process as I don't want to mess with lube and I can't afford the Dillon die set (double the price compared to other sets? why?). I also use a separate bullet seat and crimp die process. I find I can control both steps much better.

Just remember that it's the neck tension that holds the bullet, not the crimp! Be sure to use the correct bullet profile, as you can't just use any ole' 9mm bullet.

One of the big 'enemies' is bullet setback, so be sure to do the 'press test' with the thumb to ensure that you've got enough neck tension so the bullet won't be moving in the mag when you're firing.

MtnCreek said:

... .357 Sig...

How does the bottle neck affect the reloading process?

What cartridge would you compare recoil to?

I guess ballistics would be somewhere between 9mm and .357mag, correct?

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I have reloaded only a little 357 SIG but have loaded 38/45 Clerke (45 ACP necked down to 38 caliber) for a couple decades. There is no real difference in loading a bottle neck hand gun cartridge versus a straight walled handgun cartridge. Die sets are typical handgun three die sets.

As said, I have also heard some folks use a 40 S&W die to resize the body then use the 357 SIG die for the neck. I have not done that with either 357 SIG or 38/45 Clerke. I guess folks are trying to eliminate the lubrication step as 357 SIG resizing dies are steel.

I taper crimp in a separate step from bullet seating but I do that with all auto pistol cartridges.

I understand, the 357 SIG was supposed to be ballistically similar to 357 Magnum when both are using 125 grain bullets and other things being about equal.

I understand, the 357 SIG was supposed to be ballistically similar to 357 Magnum when both are using 125 grain bullets and other things being about equal.

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Yep. Same performance of a 357 magnum in an auto pistol with higher round capacity.

357 SIG is one of my favorite calibers!

On bullet seating, I've been using separate bullet seater and crimper dies on most of my handgun calibers already on a Dillon 550B, so I understand the benefit there. I should be able to use my 9mm flat point side of the Dillon 9mm seater, but I will need a .357 Sig crimp die.

For resizing, I already have a 40 S&W resizing die in carbide, so that's not a problem. Since I don't want to pay $132+ for a Dillon set of dies, I will need to obtain a .357 Sig resizing die for the second step of the resizing operation.

Question, obviously, decapping will occur when using the 40 S&W resizer, but what do you guys do with the .357 Sig resizer?

Do you take the decapping pin out?

Do you go down only part way onto the cases to resize the neck only?

zippy45 said:

Question, obviously, decapping will occur when using the 40 S&W resizer, but what do you guys do with the .357 Sig resizer?

Do you take the decapping pin out?

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If you have decapped with the 40 S&W resizer die, there is no need to have the decapping rod, the whole rod, not just the pin, in the 357 SIG resizer die. I would still full length resize in the 357 SIG die.

The mouth expanding of 357 SIG is done in yet another die from the resizing die.

Yes if the case has already been resized in the 40 S&W carbide resizer, then I can see using a .357 Sig resizer without too much resistance in a steel only resizer.

On the case mouth, since the bullet is a 9mm, can I not use my Dillon 550B 9mm powder funnel die to bell the case for bullet entry, then seat the bullet, then crimp the bullet in the last die?

Whatever you do - enjoy the caliber. I try not to get all got up in the velocity, ballistics, mine is bigger arguments. It is what it is. A nice hot compact necked down round.

Preferably get a gun with a bit longer barrel. I have a Sig P229 and while it's a great shooter, I think some of the "blast" is wasted for lack of better terms. I also have a G20 with a 6.2" .357Sig barrel - and there is less wastage. So to speak.

And this .357Sig option is in the cards:

http://thureondefense.com/index.php?option=com_content&view=article&id=1&Itemid=4

I shoot a lot of sig. Key things to me are
1) Dillon carbide die with just a touch of lube.
2) AA9 as my only powder to avoid any concerns of bullet setback
3) Lee FCD, in this caliber it really works
4) Long shank bullets. My favorite is the Rem 115 JHP.

I have shot now about 11,000 rounds out of my 229 sport in 357 sig. Great gun and just fun to shoot.

Also, don't let others BS you. The round is easy to load for and fun!

Is this the Lee FCD you use?

http://leeprecision.com/factory-crimp-die-356-358.html

I used to reload for it.

I found it a pain. Back then, there were only two dies available: RCBS and Hornady. I bought RCBS, but soon realized they would not set the shoulder back enough for the round to chamber. I had to remove metal from the bottom of the die to get it to work.

I used .40 S&W brass without issue for plinking loads. They had a shorter neck, but the round headspaced off the shoulder once reloaded so it worked fine. I drove 90gr bullets to 1900 FPS using Universal Clays and Power Pistol, but that was from a 6" KKM barrel. It was extremely accurate, placing five shots inside of 1" at 25 yards from a benchrest. My eyes were better then.

I found that maximum neck tension eliminated bullet setback. So I flared the case mouth only. That means I did not use the expander. I crimped slightly and that was good enough for my Glock because the round fed straight into the chamber and did not bounce off the feedramp.

Also, if you clean the inside of the case neck, it will hold the bullet more securely than a case with carbon fouled neck. Back then I brushed the necks with a bronze brush, then swabbed them with alcohol. Nowadays I would just wet tumble them in stainless media. Remember, pristine brass on copper makes more friction that a dirty case neck. I also discovered the benefits of nickle plated brass. The nickle increases friction still. So if you use nickle brass, your bullet setback issues will be a distant memory.

The reason people run the fired case through a .40 carbide die is so they don't have to lube. If you use a conventional .357Sig die, you have to lube. Otherwise you'll stick the case. Sonpeople run it through a carbide fie first, then through a .357 die to finish sizing and they manage not to stick the case.

You don't need a FCD. You can seat and crimp with the seater die in one step if you set up the die to remove the bell and maybe give it a teeny bit of crimp.

Today, I feel that loading the 9mm to .357 Sig pressures is a lot less of a headache and gives performance that is close enough.

I may have overlooked someone making this comment but I'll add it anyway. The cartridge uses a .355 inch diameter bullet and not a .357 inch diameter bullet. It seems confusing because it is called the 357 Sig but it uses a 9 mm diameter bullet. Use of a .357 diameter bullet will increase pressure somewhat more than the .355.

It is best to get bullets that are a true .3555 and even .356, I don't expand so it helps neck tension plus I don't even bell the mouth, I used my chanfer tool and made sure all cases had a small chamfer and with my Hornady seater I get the bullet to start straight, otherwise you can crush the case. I've tried several powders just to see if one other than AA#9 shot good and non have really beat it,so I just use it only now, plus it is noce and clean burning to boot.
I run my cases through my .40 die first then the Hornady sizer (with a little Imperial).I also have a RCBS set so I use that sizer for certain bullets.

HS-6 is a great powder for this round as well. If you want some 'flash', go with Power Pistol!! Out of my compensated G32, well, it's like a fireworks show!!

The Hornady HAP bullets are great for this round, Powder Valley has had them on sale for a while. Lots of people like the Montana Gold bullets also.

I've had a love/hate relationship (in regards to reloading) with the SIG cartridge for quite awhile. Case neck tension can be PIA. So far as die setup is concerned, I recently had a revelation. Meaning, I was pulling my hair out until I came across the following bit of info somewhere on the 'net. Remove the bbl from your pistol and drop in a factory round. Note how far in the round seats. Now try one of your sized rounds. Chances are, it won't seat as deeply as the factory one did. Mine didn't. Adjust your sizing die down and re-size your brass until it seats in the chamber the same as the factory round. For me, this required me to set my press up with a fair bit of cam-over. This simple tip, combined with correct expander set-up and a VERY light crimp, gives me perfect ammo without any setback issues.

918v said:

I used to reload for it.

I found it a pain. Back then, there were only two dies available: RCBS and Hornady. I bought RCBS, but soon realized they would not set the shoulder back enough for the round to chamber. I had to remove metal from the bottom of the die to get it to work.

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I had exactly the same problem. I just kept going back to the belt sander until I moved the shoulder back far enough to give me a decent sized neck.

Things got much easier once I discovered I could use light SWC revolver bullets sized down to .356.

Did the same thing with my RCBS sizer, turned about .03" of the bottom, Now I set it up so it just bumps the shoulder to factory numbers. I have that die locked down tight so it'll always be set. I have used Power Pistol and Blue Dot, both were great flash/bangs, accuracy wasn't too bad either but I settled on AA#9 also.

For Bullets I use Hornady 125gr Haps, Nosler 125gr JHP, Berry's 124gr fp,or 124gr hbfp, and Rainier 124 gr fp. The most accurate in my Storm Lake barrel in a XDM40 was the Hap, followed real close by the Nosler, even closer behind them were the rest.

It is a fun 50yrd caliber.

Question to me about the FCD I use. No, it is a 357 sig specific item. It ls like the FCD shown as it is a rifle type but they use a collet to crimp it.

http://leeprecision.com/factory-crimp-die-357-sig.html

You guys have convinced me that the .357 Sig actually headspaces on the shoulder, rather than the case mouth! *























I never did buy into that "headspaces on the case mouth horsehockey!"*

It does headspace on the case mouth, but only with factory new brass.

It does headspace on the case mouth, but only with factory new brass.
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I've often wondered what's the point of claiming that it headspaces off the case mouth, when the only adjustment to a .357 sizing die adjusts the bump of the shoulder? I think the "headspaces off the case mouth" is just repeated internet b.s. that was picked up from some early erroneous information that was published by Speer, or one of the other manufacturers.

No it actually does. If you look at new factory brass and compare it to fired/resized brass you'll see the new factory brass has the shoulder way far back. I think it's done to maximize neck length. But it's so far back the case actually headspaces off the mouth. The reason reloading dies do not push the shoulder that far back is it would induce casehead separation real quick.