.357 Sig Loads

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MAUSER88

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The three on the left are what I would consider "normal" looking. Now look at the three on the right namely the shoulder.

They were all sized at one time using the same die. The three on the right have a slightly collapsed shoulder. This happened after sizing, not after pushing the bullet into the brass.

Can anyone explain what happened to collapse the shoulder slightly more and would you think the three on the right with the more pronounced shoulder would be safe to shoot?

IMG_1134_zps0ff544d9.jpg
 
Not sure what would cause the shoulder to be pushed down sharper other than going a little too deep in the die ...

As far as safe to shoot ... they will be fine to shoot ... I would pull the barrel out of your gun and drop some of both in the chamber to see how they look as far as chambering goes...

What brand of die are you using ... if it pushes some down and not others ... just not sure how that could happen ... are you sure you are pushing the brass into the same die in the same fashion each time?

I just went and looked at a big coffee can of 357 SIG I had resized not too long ago ... they all look like the ones in the left of your photo...
 
RCBS dies. They do drop in and right out of the barrel. Funny but this only happened to about 12 of the nickle cases I resized and loaded. I didn't load the rest of them out of concern. None of the brass cases did this.
 
I'm no expert, but if they chamber-check I'd assume they'd just fireform to the chamber without an issue?

Larry
 
All my cases are nickel too... I looked at quite a few to see if I could find any like your right (photo) ones...none that I could find ... I use RCBS dies too ... I use a lanolin/alcohol lube sprayed in a ziploc bag ... I just don't see lube making a uniform shoulder like that ... all lube dents that I've ever seen are in different locations around the shoulder... I've just never seen any on pistol brass ...
 
If you're certain it didn't happen while seating/crimping your bullets, my best guess would be that some of your cases are too long. The slightly collapsed shoulder itself wouldn't concern me too much; as long as the rounds chamber OK, the slightly collapsed shoulder would probably just manifest itself in misfires, if at all.

If the cases ARE too long it's a whole 'nother story. Firing them could lead to serious pressure spikes and even a kaboom. If the case mouth was pushed back by hitting the step during resizing, the case could be pushed into the leade when fired which can prevent the bullet from leaving the case normally and cause pressures to skyrocket.

Measuring case length at this point won't really tell you anything since the case has been slightly "telescoped" into itself decreasing length.

How many times have these cases been fired? How hot were the loads?
Have you ever trimmed them?
Did you measure the cases before seating bullets?

You can probably get a reasonably good measurement of your case length even with a bullet seated, if they're up close to maximum, I'd probably pull the rounds just to be safe.

If you've still got a bunch of cases that haven't been resized, try measuring some for length before you size 'em. Segregate your cases by length then run 'em through the sizing die and see if there's any correlation as to which cases get the "collapsed" shoulders.
 
I would vote for a slight OAL difference. Remember, the shoulder on this is teeny. it really wouldn't take much extra case to set it back. Were all 6 of these fired from the same gun the last time? If not, you could be dealing with a fire-forming difference. I have read that due to early popularity, the tolerances from one gun manufacturer to another were markedly different. I'm sure within SAAMI guidelines, but still different.

On another note, ain't it a peach of a round? I love the crisp muzzle flip and the head turns I get from the sharp report!
 
If the case mouth was pushed back by hitting the step during resizing, the case could be pushed into the leade when fired which can prevent the bullet from leaving the case normally and cause pressures to skyrocket.
Click to expand...

To the best of my knowledge there is no step in the RCBS 357 SIG sizing dies ... and this cartridge is supposed to head space on the case mouth... ( I know this is not 100% true because I have made a few case from 40 S&W in which the brass come up somewhat shorter... it still worked for some mild loads) ... the brass would have to be way long and have a heck of a crimp to shove it into the leade ....
 
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@ JimKirk
As I said, "my best guess".

To be honest, it looks a lot like a "too much crimp" situation, but the OP said it was like that before seating and crimping.

I'm with you, I'd really like to see the deformation on some of the sized but not yet loaded cases.
 
Swampman ... didn't mean to to come across as I did ... my bad .... sometimes my fingers and mind run on different tracks ... sometimes they meet and other times ... not so well ...

I did go out to the shop this evening and pull my RCBS 357 SIG sizing die apart and it was smooth as a baby's rear all the way up to where the threads start, which is quite a ways farther up the die ... my die also has the same basic shoulder as displayed on the cases(left) in the photo... since the OP brass(Left again) looks normal ...there is no way the die is machined wrong or all the brass would have the shoulder of the (right) brass...

I'm going to go with Swampman(and others) on this and say that those(right) few brass are a little longer than the other brass and that when you crimped it pushed the brass down moving the shoulder...

None of the bullets I use for my 357 SIG have a cannelure so I don't crimp ... I don't flare my brass either ... I mostly use the Hornady XTP bullets ... and have not needed a crimp so far ... I don't take my cartridges in and out either like would a cop or law person... so set back is not a problem for me ...
 
@JimKirk
No offense taken, honestly it was the only scenario I could come up with that would cause some of the necks to collapse during resizing while others looked normal.

I still can't come up with anything better to explain how cases could be deformed like that before seating and crimping. :confused:
 
I'm gonna guess it's the RCBS dies. They're known to have issues with 357sig. Great dies for every other caliber, but not this one. Do some searching around the web, you'll see what I mean.

May want to do the "thumb test" to make sure you won't be having any setback issues, cuz I'm going to guess that those 3 on the right may not have the same neck tension as the other 3 on the left!
 
As Sherlock Holmes might say, ELEMENTARY !

The cases that you presented provide a challenge of deduction to other 357 Sig reloaders.(Pun Intended) All of the above offered explanations are all plausible to some extent, ranging from excessive case length to die imperfections (least plausible IMHO). Obviously 3 of the case show a slight deviation in shoulder concentricity which I too speculate was caused by excessive lube or residue on those cases which hydraulic like pressures distorted.
Although they may be okay to shoot, personally I would just pull the 3 bullets and do a clean resizing with less lube.
Let us know what you find out after further investigation.
 
I'd like to ask you to test those 3 with the "thumb test" to test for testback. I'm wondering if that bulge has reduced the neck tension enough to allow the bullet to easily be set back by thumb pressure against the back of the cartridge & the bullet on a bench surface or something hard...
 
I'm just starting to load 357 Sig, how much pressure/force are we talking about for the "thumb test"? I made some inert test rounds today and I could get the bullet to go back into the case, but I was leaning on them quite hard. The bullets I tried were Xtreme 124gr hollow points. I'm thinking that they don't quite have the proper amount of bearing surface. They have a profile close to a normal .355" round nose.

I'll try the Rainier 115gr hollow points I have next. They look more like the needed profile for the 357Sig
 
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