Loading .357 Sig

What do you guys use for bullets? I have these Georgia Arms cast .357 flat point 125 grain bullets that I picked up really cheap. I’ve been loading them in .357 mag and shooting in my SP-101, but I don’t want to use them in my K frames. I decided to try and load .357 Sig with them. It’s the 125 grain cast bullet over a charge of 5.3 grains Universal. I loaded about three mags full and took them out to the range and tried them. They shot beautifully in my P239, so last night I loaded 150 more and took them to the range today. Turns out they’re pretty accurate too. The group on the bottom part of the lower right plate was slow fire from 21 feet with my elbow resting on a gun rug. I shot at the group free hand a few times and most of the flyers are from that. The main part of the group is 21 rounds(3mags worth). I shot them all up and had to come home and load more just to take the picture

I don't shoot allot of 357 sig but when I do reload for it, I use 125-130gr 38 super bullets (from Missouri and Berry's as I recall). I usually load them like hot 9mm and really don't push their limits.

Your load is just fine.

Personally, I only load jacketed, but that is because I have a few ported pistols and a suppressor for the MP5. It just makes everything easy to clean

BTW, there is no reason that those same projectiles can not be used in your K-frames

Groo here
Nice to see you load 357sig.!
Here is a hint or two......
Size the 357sig with a 40 S&W carbide die.
Then size the neck like a rifle.
Second , the 357sig head spaces on the case mouth OR the shoulder.
[usually the shoulder] .
Pul your barrel and set the shoulder back just enough for the case to be flush with the hood.
This will allow you to crimp the bullet like a revolver.
Look up the sig drawings [not the U.S. ones] to find this.

colt_saa said:

Your load is just fine.

Personally, I only load jacketed, but that is because I have a few ported pistols and a suppressor for the MP5. It just makes everything easy to clean

BTW, there is no reason that those same projectiles can not be used in your K-frames

Click to expand...

I thought you didn’t want to use them because of flamecutting from the lighter bullet. Is that just an issue with hotter loads? I’d like to use them with my 66-4 and a soon to be acquired 19-2 because I have plenty of them.

Groo01 said:

Groo here
Nice to see you load 357sig.!
Here is a hint or two......
Size the 357sig with a 40 S&W carbide die.
Then size the neck like a rifle.
Second , the 357sig head spaces on the case mouth OR the shoulder.
[usually the shoulder] .
Pul your barrel and set the shoulder back just enough for the case to be flush with the hood.
This will allow you to crimp the bullet like a revolver.
Look up the sig drawings [not the U.S. ones] to find this.

Click to expand...

Hi Groo. Thanks for the input. Sorry I didn’t get back to the points you brought up sooner, but I had to reread and digest it a bit to understand it I’m relatively new to reloading, so bear with me a little. I’ll try the .40 sizing die when I get home tonight and see how that works. I was having trouble with the .357 sizing die scoring the cases, so that’s why I broke out the brand new Starline so I wouldn’t have to run my once fired cases through the deprimer/sizer.
I haven’t loaded any rifle yet, so I’m not sure about neck sizing like a rifle. I just run it through the powder through/flaring die, then seat and crimp the bullets. I’m not really happy with the crimp I’m getting, but it seems to be working. I haven’t had any bullets jumping crimp and only had one FTF and I think that was because I buggered the case a little during the loading process.

How do you set the shoulder? I thought that was not something you could change.

Thanks again for sharing your knowledge with me

You can use the 125 gr bullets in 38 spl loads or mid range 357 magnum loads . Just don't make " hot 357 loads " using those lighter bullets .

tlawler said:

I thought you didn’t want to use them because of flamecutting from the lighter bullet. Is that just an issue with hotter loads? I’d like to use them with my 66-4 and a soon to be acquired 19-2 because I have plenty of them.

Click to expand...

Flame cutting is not a function of bullet weight

It is a function of large charges of certain powders.

Those large charges just happen to be common only when pushing lighter weight projectiles at Full MAGNUM velocities.

Not picking on you, but I really hate the term "HOT", it almost sounds like it is something outside of the SAAMI industry standards when truly we are only talking about cartridges at FULL Magnum performance

Flame cutting gets to a point and pretty much stops. I do not believe there has been catastrophic S&W firearms failures due to flame cutting. At least none that I can recall

The issue with older K-frames has been the flat spot (weakness) in the bottom of the barrel developing a crack in the forcing cone.

Even that is an overblown issue

Millions and millions of K-frame Magnums have been in service with both Law Enforcement and Civilians firing tens or even hundreds of millions of full power magnum loads over more than half a century now and the Internet only turns up a small handful of examples

Don't we have to believe that as Metallurgy and Manufacturing techniques advanced over the last 60 or 70 years that Smith and Wesson would learn from that and their products would improve and advance in durability along with those new techniques?

Yes, forcing cones crack, but nowhere in the proportions that the Internet Lore would lead you to believe

tlawler said:

Hi Groo. Thanks for the input. Sorry I didn’t get back to the points you brought up sooner, but I had to reread and digest it a bit to understand it I’m relatively new to reloading, so bear with me a little. I’ll try the .40 sizing die when I get home tonight and see how that works. I was having trouble with the .357 sizing die scoring the cases, so that’s why I broke out the brand new Starline so I wouldn’t have to run my once fired cases through the deprimer/sizer.
I haven’t loaded any rifle yet, so I’m not sure about neck sizing like a rifle. I just run it through the powder through/flaring die, then seat and crimp the bullets. I’m not really happy with the crimp I’m getting, but it seems to be working. I haven’t had any bullets jumping crimp and only had one FTF and I think that was because I buggered the case a little during the loading process.

How do you set the shoulder? I thought that was not something you could change.

Thanks again for sharing your knowledge with me

Click to expand...

I load 357 SIG in a five station press

Station one is a 40S&W carbide sizer where depriming also occurs
Station two is a 357 SIG sizing die. Primimg also occurs at this station
Station three flares the mouth and drops the powder
Station four seats the projectile
Station five applies a collect crimp to the cartridge


By using the two sizing dies you let the carbide die do the majority of the work. The 357 SIG die is adjusted high enough to just resize the neck. Leaving the body alone

Test that brass in your pistols. In some cases the 357 SIG die will need to be adjusted a tiny bit farther down in order to push the shoulder back if you have a tight chamber. If you have more than one 357 SIG firearm you set the sizing dies for you most troublesome chamber.

I use a Lee Factory Crimp die in that final stage. The FCD imparts a Collet crimp to the case. This allows the use a much wider range of projectiles over what neck tension alone holding the projectile in place can work with.

Once you get your rhythm going, 357 SIG is not that big a deal to load. I have been hand loading the 357 SIG cartridge since about 1993 so it all seams routine now a days

tlawler said:

I was having trouble with the .357 sizing die scoring the cases, so that’s why I broke out the brand new Starline so I wouldn’t have to run my once fired cases through the deprimer/sizer.

Click to expand...

Clean your sizing die.

Dirt and debris from your fired cases is what causes the scoring.

Do you tumble your brass prior to hand loading?

I had trouble with a new sizing die scoring the side of the cases . From looking at the score marks running full length of the case the problem was just inside the sizing die . I chucked a case in an electric drill , smeared old style tooth paste , the kind that " whitens " teeth (supposedly contains a small amount of a very very fine emery) around the inside of the sizing die and some on the case . Inserted the case into the sizing die and turned on the drill , in short bursts . It took about 3 cases and 3 daps of tooth paste , but it smoothed / polished the inside of the die . Maybe this will help , if your brass isn't dirty . Regards, Paul

Just to add to the befuddlement of reloading 357 Sig



Loading the .357 Sig - MassReloading


Reloading .357 SIG for the Glock 20 – Ultimate Reloader

colt_saa said:

I load 357 SIG in a five station press

Station one is a 40S&W carbide sizer where depriming also occurs
Station two is a 357 SIG sizing die. Primimg also occurs at this station
Station three flares the mouth and drops the powder
Station four seats the projectile
Station five applies a collect crimp to the cartridge

Click to expand...

I have loaded the 357 SIG for 10 years using steps that are identical to yours, except I deprime and prime separately.
The Lee 357 sizing die is hard enough for final sizing/shoulder setback without the use of case lube.
I've preached to anyone who will listen about the advantages of Lee collet crimpers, but very few seem to listen.

FYI- Don't try to load Remington Golden Sabre bullets in a 357 SIG. the neck is too short to hold them.

For pure fun at the range I have found Rainier's 124gr plated HP to be an excelled and inexpensive practice bullet. The LEE Factory Crimp (collet-style) Die as indicated previously is, to me, the answer to a fine crimp regardless of the type of bullets used. Running clean cases through a 40 S&W sizing die 1st is also a great idea. I prefer to use a dedicated expander (Hornady) for this caliber and avoid the LEE powder through die for this function, but that is a personal preference.

The 357 SIG lends itself to quite a few bullet designs and weights, powders, velocities and power levels, from mild to WILD. What I consider to be HOT basically mimics factory loadings (i.e., 125gr Gold Dot) and 357 Magnum ballistics. Been slowly attempting to develop a load using the Polycase ARX 9mm 65gr bullet with some success, OAL and seating/crimp being the questions. Maybe they'll come up with some load data eventually (or, better yet, a dedicated 357SIG round!).

Cheers!

P.S. The other thing that really helps reloading 357SIG is the l.e. wilson headspace gauge. I run cases through it both before bullet seating & after the LEE collet-style crimp, just to make sure.

I ran a few cases through the .40 die and deprimed just to try it out. I think what I’m going to do is set up a single stage press to be the “fifth station” for my Lee Classic 4 hole. I need to clean up my .357 sizer first also before I run any more batches. I loaded up 200 the other night with the new starline and skipping the resizing. I’m going to go shoot them and set up with the 5 station when I get back. We are getting ready to go on a 7 day Caribbean cruise, so things are a bit hectic around here.

I've used a bunch of diff bullets in 357sig since I started loading for it. Anything truncated cone works. With lead or coated lead, just make sure you have enough driving band in the short case neck for good neck tension. I load on a 550 with Dillon dies, so just like any other service round for me.
Yep, my p239 is one of the most accurate semi I own.

watch for speer brass has a smaller flash hole and sometimes bends deprimer pin tip. ran into this when i started reloading the 357 sig . i run my cases through a lee 40 cal bulge buster die works great.

Never heard of an unsupported chamber in 357 SIG...

Scuba16 said:

watch for speer brass has a smaller flash hole and sometimes bends deprimer pin tip. ran into this when i started reloading the 357 sig . i run my cases through a lee 40 cal bulge buster die works great.

Click to expand...

Never heard of an unsupported chamber in 357 SIG but I guess it's possible: have the bulge buster as well, but I've really only used it for 380 ACP so far... Thanks for the tip re: Speer brass flash holes: does that also apply to their 40 S&W brass as well?

I must be lucky: virtually none of my 40 S&W brass has exhibited any bulges, even the misc. range brass I've accumulated over the years. I'm just about ready to just shoot 'em and leave 'em this next time as my SUB2000 is finally broken-in: the "new barrel", that is!

Cheers!

To the OPs question: I’ve used Zero 125 grain and Rainer 147 grain bullets over AA#7 and CFE-P powder with good results. I shoot them out of SIG P239/40 & P226/40 using new SIG conversion barrels. I use the 40SW mags in both guns without issue.
I resize, de-prime, prime and flare separately using the 40SW/357SIG die method others have pointed out. Then load on my 650 when I have time for concentrated work.

I’m really liking the 357Sig and the flexibility it allows of bullet usage. I trying the work up a 130 grain loading using .356 bullets from my 38SUPER loads.