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Old 01-12-2021, 12:37 PM
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Default Questions about reloading the 357 Sig cartridge

From what I am gleaning from most reloading data sites, is that almost any 100-124/5 gr 9mm JHP bullet can be used to reload the 357 Sig. Is this a reasonable observation?

For those that reload 357 Sig, how much of the overall length of the bullet needs to be dedicated to the bearing surface as opposed to the bullet nose?

As always, thanks in advance for your help!
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Old 01-12-2021, 01:56 PM
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For the most part my experience has been that in bullet weights 115gr & above flat pointed (i.e., Berrys HBFN-TP for practice/range use) or hollow pointed bullets (i.e., XTP, Gold Dot for HD/PD) work best for 357 SIG because the recommended OAL is typically 1.135" (1.140" for 147gr).

Round nosed or conical bullets don't always allow enough of the bullet past the ogive (some refer to it as the caliber diameter) to secure within the case. Pushback can also be a factor with 357 SIG velocities: I use the LEE FCD which is a collet-style crimp die (often used with bottleneck rifle cartridges) with much confidence.

If you take a look at the profiles of bullets specifically designated as being for 357 SIG I think you will notice their similarities.

There are other posts on this sub-forum about dies you may find instructional as well.

Cheers!
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Old 01-12-2021, 06:14 PM
cowboy4evr cowboy4evr is offline
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I will offer up a suggestion , what I found has helped me . I found a case gauge very helpful . Occasionally I had a case that the sizing die couldn't totally resize . A slight bulge was still there near the base . The last time I resized / deprimed 50 cases I had 5 that would not fit into the case gauge . I bought the LEE push through sizer . It fixed my problem . I also found that Berry's Bullets sized .356 , heavy plated , for 357 sig the most accurate vs .355 . For powders I liked Accurate #9 and Alliant Blue Dot . That has been my experience in my Sig P320 converted to 357 sig . Regards Paul
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Old 01-12-2021, 07:23 PM
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That's the one: their No. 00335. IMHO the Wilson Case Gage is a must for reloading 357 SIG as well. I routinely check the cases after sizing, before new primers, expansion, powder, seating & the crimp. And after all's done, as well. I'll plunk test a couple in my 357 SIG barrels before I get into any real "production". There are variations in chambers, and with a bottleneck cartridge this can make a difference.

Belt & suspenders...maybe? So far all my 357 SIG reloads have fired perfectly.

A side note: resizing the cases with a 40 S&W carbide die 1st, then with the 357 SIG sizing die (most are not carbide) works very well for me. No need to lubricate so far.

Cheers!
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Old 01-12-2021, 10:41 PM
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Thanks for the information. I already have my dies and a Lee FCD, all that is missing are the bullets! I've noticed that it appears as though the ogive of the round nosed bullets tends to put the bearing surface below the case mouth. I have about a thousand Hornady HAP bullets that I'm trying to get a feel for. All that is missing at the moment is the 357 Sig barrel for the 229, so I can't yet experiment with a "plop" test!
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Old 01-12-2021, 11:27 PM
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Those HAPs should work just fine. They are, basically, an XTP without the cuts for flutes.
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Old 01-12-2021, 11:39 PM
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Originally Posted by lrrifleman View Post
From what I am gleaning from most reloading data sites, is that almost any 100-124/5 gr 9mm JHP bullet can be used to reload the 357 Sig. Is this a reasonable observation?

For those that reload 357 Sig, how much of the overall length of the bullet needs to be dedicated to the bearing surface as opposed to the bullet nose?

As always, thanks in advance for your help!
Not any 9mm but truncated cone above 115gr. You need enough bearing surface inside the case neck, but that isnt the issue. The issue is getting enough bearing surface inside the case neck & still make oal.
The only carbide dies I am aware of are Dillon. Expensive but worth it to me.
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Old 01-13-2021, 08:19 AM
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The short neck of the .357 Sig requires some care when selecting a bullet for reloading. The common round nose 9mm projectiles can't be used as their ogives don't permit maximum contact with the case neck.

A bullet with a straight shank (the Hornady HAP or XTP is an excellent choice) is necessary for the case to get a proper grip on the projectile. I made up the attached photo a few years ago to show the difference.
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Old 01-13-2021, 08:17 PM
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The short neck of the .357 Sig requires some care when selecting a bullet for reloading. The common round nose 9mm projectiles can't be used as their ogives don't permit maximum contact with the case neck.

A bullet with a straight shank (the Hornady HAP or XTP is an excellent choice) is necessary for the case to get a proper grip on the projectile. I made up the attached photo a few years ago to show the difference.
You can load a RN if the bullets are light enough, below 115gr.
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Old 01-14-2021, 02:32 AM
STORMINORMAN STORMINORMAN is offline
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I would like to concur regarding the use of lighter bullets: in my experience many 90 and 95gr JHPs & SJHPs load up with no problems re: OAL or sufficient bullet contact with the case neck (fredj338 refers to this as the "bearing surface") to insure they can be properly seated and crimped.

Even with START loads these projectiles are moving at relatively speedy velocities (as in 1,400 fps) and the recoil is minimal. Fun, fun at the range.

Cheers!
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Old 01-14-2021, 02:58 AM
Racer X Racer X is offline
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I'm now scratching my head. So, lighter bullets will have MORE "bearing surface"?

Just getting into reloading, and .357 SIG is one of the calibers I will be doing.
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Old 01-14-2021, 06:03 AM
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Lightbulb Not exactly, but...

No, not because they are light, but because they are usually short enough that there is sufficient length past the ogive that extends into the neck of the case to be firmly seated and crimped.
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Old 01-14-2021, 06:37 AM
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I'm now scratching my head. So, lighter bullets will have MORE "bearing surface"?

Just getting into reloading, and .357 SIG is one of the calibers I will be doing.
No not more bearing surface

357SIG has a very short neck. many heavier (longer) projectiles have their bearing surface ending up too far inside the case, thus it is not aligned in the neck for good tension.

I started shooting 357SIG in 1993. I was working in Dallas County and I had access to some of the Texas DPS guys that were involved with the evaluation of the cartridge. That is where I shot my first SIG P229

I used to go through LOTS of 357SIG (6000+ annually). I have loaded tens of thousands of rounds over the years. These days it loads just as smoothly as 45 ACP or 357 Magnum

lrrifleman,
As STORMINORMAN points out that Lee FCD imparts a collet crimp that virtually eliminates neck tension issues as long as the profile of your projectile puts some of the bearing surface at the case mouth. Before discussing with LEE about the possibilities of a collet crimp die for this cartridge, I reduced the diameter of the expander plug by a little over .001" to try and increase neck tension with some of the iffy projectiles

The Montana Gold 357SIG projectiles are great as are the Hornady XTPs and HAPs. It is that truncated cone shape that works so good with this cartridge. I am not sure if I ever loaded plated in this cartridge due to the velocities.

I have a cute 90 grain JHP that leaves my SIG X5 at 1700 FPS when pushed by a nice charge of Power Pistol. It is Extremely accurate in my SIG P229 Sport



Prior to our current Constitutional Crisis this projectile was very reasonably priced even if I only bought a few thousand at a time



That 90 JHP load moves out even faster from my 8.9" MP5, though I have not chronographed it

I have not loaded anything above 147/150s though I have a buddy that goes over 160 grains with a custom made JHP. I only go heavy for suppressed use. Most of what I load are 124/125s or the 90s

I load on a five stage progressive press and like STORMINORMAN my first die is a carbide 40 S&W sizer. Without that the handle pressure on my press was excessive. Now I do lube the cases with Hornady One Shot. Every few hundred rounds I give a little squire into the 5 gallon bucket of grass and do a quick hand stir


Station 2 is the 357SIG sizing die and priming. I did have a chance to try the Dillon carbide die on the press but it made no appreciable difference in handle force needed over a steel sizer even though it cost 4-5 times as much

Station 3 drops powder and expands the case mouth

Obviously I seat and crimp at stations 4 and 5 respectively
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Old 01-14-2021, 12:09 PM
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No not more bearing surface

357SIG has a very short neck. many heavier (longer) projectiles have their bearing surface ending up too far inside the case, thus it is not aligned in the neck for good tension.

I started shooting 357SIG in 1993. I was working in Dallas County and I had access to some of the Texas DPS guys that were involved with the evaluation of the cartridge. That is where I shot my first SIG P229

I used to go through LOTS of 357SIG (6000+ annually). I have loaded tens of thousands of rounds over the years. These days it loads just as smoothly as 45 ACP or 357 Magnum

lrrifleman,
As STORMINORMAN points out that Lee FCD imparts a collet crimp that virtually eliminates neck tension issues as long as the profile of your projectile puts some of the bearing surface at the case mouth. Before discussing with LEE about the possibilities of a collet crimp die for this cartridge, I reduced the diameter of the expander plug by a little over .001" to try and increase neck tension with some of the iffy projectiles

The Montana Gold 357SIG projectiles are great as are the Hornady XTPs and HAPs. It is that truncated cone shape that works so good with this cartridge. I am not sure if I ever loaded plated in this cartridge due to the velocities.

I have a cute 90 grain JHP that leaves my SIG X5 at 1700 FPS when pushed by a nice charge of Power Pistol. It is Extremely accurate in my SIG P229 Sport]

Prior to our current Constitutional Crisis this projectile was very reasonably priced even if I only bought a few thousand at a time

That 90 JHP load moves out even faster from my 8.9" MP5, though I have not chronographed it

I have not loaded anything above 147/150s though I have a buddy that goes over 160 grains with a custom made JHP. I only go heavy for suppressed use. Most of what I load are 124/125s or the 90s

I load on a five stage progressive press and like STORMINORMAN my first die is a carbide 40 S&W sizer. Without that the handle pressure on my press was excessive. Now I do lube the cases with Hornady One Shot. Every few hundred rounds I give a little squire into the 5 gallon bucket of grass and do a quick hand stir

Station 2 is the 357SIG sizing die and priming. I did have a chance to try the Dillon carbide die on the press but it made no appreciable difference in handle force needed over a steel sizer even though it cost 4-5 times as much

Station 3 drops powder and expands the case mouth

Obviously I seat and crimp at stations 4 and 5 respectively
The diff with the dillon carbide is I dont need case lube or the extra step of a 40 sizer. I think the cost is worth removing steps.
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Old 01-14-2021, 12:59 PM
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The diff with the dillon carbide is I dont need case lube or the extra step of a 40 sizer. I think the cost is worth removing steps.
Fred,
On a progressive press, the 40 sizer does not add another step.

Everything happens with a single pull of the handle whether there are 4 dies mounted or 5

I do not NEED to use lube either with my 5 die setup, but when I use One Shot case lube, handle pressure is reduced. So fatigue is reduced and I can load for a longer period of time producing more rounds in a single session.

To me that makes the $15 can of One Shot lube a mandatory item. That one can lasts many tens of thousands of rounds.

I use One Shot on every cartridge that I hand load. Even with carbide dies

Why would you possibly choose to exert MORE effort when you do not have to?

Other than to save that $15 expenditure every year or two
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Old 01-14-2021, 07:44 PM
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This is fantastic info everyone! One of many reasons I love this place. My Lee press is a 5 station press, the LoadMaster. I can easily set up my .357 Sig die plate with station 1 a carbide .40 sizer.
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Old 01-14-2021, 11:15 PM
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Fred,
On a progressive press, the 40 sizer does not add another step.

Everything happens with a single pull of the handle whether there are 4 dies mounted or 5

I do not NEED to use lube either with my 5 die setup, but when I use One Shot case lube, handle pressure is reduced. So fatigue is reduced and I can load for a longer period of time producing more rounds in a single session.

To me that makes the $15 can of One Shot lube a mandatory item. That one can lasts many tens of thousands of rounds.

I use One Shot on every cartridge that I hand load. Even with carbide dies

Why would you possibly choose to exert MORE effort when you do not have to?

Other than to save that $15 expenditure every year or two
I supposecit deoends on the press, but adding a 40 to my 550 or 650 woudnt work. I do spray a bit of OS on a few cases but the carbide dies do work well withought.
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Old 01-15-2021, 07:17 PM
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From what I am gleaning from most reloading data sites, is that almost any 100-124/5 gr 9mm JHP bullet can be used to reload the 357 Sig. Is this a reasonable observation?

For those that reload 357 Sig, how much of the overall length of the bullet needs to be dedicated to the bearing surface as opposed to the bullet nose?

As always, thanks in advance for your help!
Yes. I've loaded 9mm speer 124 grain and 9mm armscor 124 grain, both worked well.

As for the second question, I interpret that as how far the bullet needs to be seated. I seat the 9mm 124s just deep enough to feed reliably in my magazine, which of course may vary across brands. I shoot a p320. Keep in mind that the 9mm bullets seat deeper than the 125 grain 357 sig specific .355 bullets, so your pressure is going to be slightly higher for any given load.
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Old 01-15-2021, 07:27 PM
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Originally Posted by Coastie762 View Post
The short neck of the .357 Sig requires some care when selecting a bullet for reloading. The common round nose 9mm projectiles can't be used as their ogives don't permit maximum contact with the case neck.

A bullet with a straight shank (the Hornady HAP or XTP is an excellent choice) is necessary for the case to get a proper grip on the projectile. I made up the attached photo a few years ago to show the difference.
This is the proper way to go, but round nose 124 grain 9mms can definitely be loaded and shot accurately in 357 Sig. I've put a few thousand downrange with maximum longshot charges and only had some slight bulging here and there after about 4 or 5 reloads of the brass. Never had a problem with bullet setback or unintentional pressure problems. Obviously if you don't feel comfortable doing it, then don't. I'm just always trying to save money when I can.
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Old 01-15-2021, 10:46 PM
STORMINORMAN STORMINORMAN is offline
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I'm really confused! 357 SIG MAX loads of Longshot for 124gr XTPs per Hodgdons data is 9.3 gr @ 1,429 with a 4.00" barrel: pressure is listed as 37,900 PSI.

Their START for 357 Magnum with Longshot and a 125gr XTP is 8.2 gr @ 1,529 and their MAX is 9.7 gr @ 1,647 in a 10.00" barrel: pressure shown as 42,000 CUP.

Nonwithstanding the different way pressure is expressed, doesn't the 357 Magnum case have a significantly greater volume (26.2) than the 357 SIG (19.5)? Especially when using what are basically the same size bullets? There's the lack of a cannelure on the .355, but the profiles are really not that different...

I'm not trying to argue apples vs. oranges here, but shouldn't a case THAT MUCH smaller (as in 25+%) in volume generate significantly higher pressures were the powder loads to be equal... Say, using 9.2 gr which is halfway between the Magnum's START and MAX? Wouldn't the smaller case pressure be higher?

We get routinely concerned with an unintentional increase in pressure when bullets are loaded deeper by relatively minute amounts (typically measured in thousandths, even hundredths of an inch?), nothing that would ever result in a 25% decrease in case volume?

P.S. From what I can determine that MAX Magnum load pressure of 42,000 CPU 1.516 - 17,902 = 45,770 PSI (approximately?)

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Old 01-16-2021, 10:34 AM
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I'm really confused! 357 SIG MAX loads of Longshot for 124gr XTPs per Hodgdons data is 9.3 gr @ 1,429 with a 4.00" barrel: pressure is listed as 37,900 PSI.

Their START for 357 Magnum with Longshot and a 125gr XTP is 8.2 gr @ 1,529 and their MAX is 9.7 gr @ 1,647 in a 10.00" barrel: pressure shown as 42,000 CUP.

Nonwithstanding the different way pressure is expressed, doesn't the 357 Magnum case have a significantly greater volume (26.2) than the 357 SIG (19.5)? Especially when using what are basically the same size bullets? There's the lack of a cannelure on the .355, but the profiles are really not that different...

I'm not trying to argue apples vs. oranges here, but shouldn't a case THAT MUCH smaller (as in 25+%) in volume generate significantly higher pressures were the powder loads to be equal... Say, using 9.2 gr which is halfway between the Magnum's START and MAX? Wouldn't the smaller case pressure be higher?

We get routinely concerned with an unintentional increase in pressure when bullets are loaded deeper by relatively minute amounts (typically measured in thousandths, even hundredths of an inch?), nothing that would ever result in a 25% decrease in case volume?

P.S. From what I can determine that MAX Magnum load pressure of 42,000 CPU 1.516 - 17,902 = 45,770 PSI (approximately?)
Difference is the barrel length. Lee also has the 9.3 grain charge with a 124 grain bullet for 357 Sig but their test barrel is an actual pistol barrel. I have no idea why Hodgdon publishes a 10 inch barrel in their PISTOL section. They should have two difference clocks for 357 mag, one for pistol and carbine.

With a short barrel like 4 inch, you will need on average much more powder to get an equivalent fps because the short barrel evacuates pressure much more quickly, because it is short. Also, that 9.3 grain longshot charge for Sig is underclocked. It says 1,429 fps but i got an average of 1,469 in a 3.9 inch barrel, and a high of 1,513.

Don't pay attention to CUP pressure ratings, you'll give yourself a panic attack. Just get a chrono, and then watch both your fps and felt recoil. That is a better, faster indication of danger. If Lee says 9.3 grains of longshot will give you 1,429 with a 9mm round nose bullet, which it won't, best start on the low end at 8.5 and then do a chronograph to see where you really are, and then go for there
Same with the weird 10 inch 357 mag data. Me personally, i took my 4 inch and started on the highest charge in that situation because i knew the 10 inch barrel velocity and pressure was far beyond mine and were overstated. It was, and then i increased the charge from there until i got what i wanted. At that point felt recoil was dimilar to factory 357, a bit sharper since Longshot burns faster, and the velocity for 180s was in the same vicinity of stated factory 180 grain loads. I inspected the brass, which looked fine, deduced that i was safe, and stopped pushing the charge. I could probably go higher but i am fine with 540 ft/lb 180 grain loads, not much will walk away from that.
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