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Widder, SASS #59054

Blew up a pistol today: UPDATED (2nd page)

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Today, my SIG P320 met its waterloo.

This is .357 SIG ammo, NOT .357 Magnum.

 

I was shooting some .357 SIG home-brew.

125 gr. speer jacketed bullets

11.7  AA9 powder charge. 

 

The unexpected happened twice.  BOTH times was with .40 S&W brass necked down to .357 SIG.

I had already fired about 10 rounds with no incident.  AND, I had also fired the SAME ammo in my

SIG P229, with no incident.

 

1st incident:  I had a blow out at the bottom of the case. The case stuck in the chamber and was easily

extracted.   The EXTRACTOR also dislodged from its slot position but stayed in the pistol and was not

damaged.

In all appearances, the only problem seem to be that the casehead had a blowout.

 

2nd incident:   after careful examination of the P320, all seemed well and I continued to fire it

a few more times (@ 10)  with no issues.   THEN IT HAPPENED... another case blowout.  But this time

the EXTRACTOR actually broke off, the magazine blew out the bottom of the pistol grip AND the

floor plate and spring and follower all blew out of the magazine.  AND, the right side of the polymer

grip cracked in two places, high on the grip area.

Oddly, the case remained in the chamber again, but when I poked it out with a rod, the WHOLE

casehead was separated and the straight wall of the case remained in the chamber.

I removed the case body rather easy.

 

In BOTH incidences, the bottom portion of the case had separated but the side walls of the brass

did not split.

Both cases were formed from .40 S&W brass.

I was shooting the same ammo from both my P320 and P229.   The P229 had no incident.

   

SPEER reloading manual list load data for this 125 gr bullet with AA9 at 13.1 to 14.6

 

LEE reloading manual list load data for this 125 gr bullet with AA9 at 11.7 to 13.0

 

I pulled 2 remaining UNFIRED rounds.  My AA9 measured 11.7 and both bullets were 125 gr.

I do not have (nor ever have) .357 bullets weighing more than 125 gr. 

 

Personally, I think it was the reformed .40 brass that might have caused some increase in pressure.

I conclude this because .357 brass formed from .40 brass is a little shorter.   And this may have caused

the problem.

BUT, thats the only thing I can think of for this issue.   

I guess its possible for the brass to be defective or old, but it didn't split.  Its just blew out the bottom.

 

If ya got a comment, feel free to share.   And THANKS!

 

..........Widder

 

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You sure the rnd was fully chambered? 

Section a .40 S&W case and a .357 Sig. 

You'll see a difference in the web.

Have you called Sig yet?

Dump that ammo.....

OLG 

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9 minutes ago, Widder, SASS #59054 said:

I pulled 2 remaining UNFIRED rounds.  My AA9 measured 11.7

 

While that most likely means the two that had separation were within tolerance it is not positive proof.  Maybe set up your reloading station and throw 50 or 100 charges and see what they weigh.

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LUMPY:  as much as I could 'sense', everything felt normal it the function of the pistol.   And

I only pulled the trigger once the previous shell had ejected and the slide closed....or so I think.

In both incidents, I was not speed shooting.   Each shot was a typical, show timed shot at a target.

I will contact SIG on Monday.

 

RED:  I think there may have been too much energy for that .40 brass, which had been necked down.

 

..........Widder

 

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First glad you are OK

 

Is it possible you had an out of battery discharge? Search of the web shows case failures in P320s are more common than I would have thought.

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Check of SAAMI specs shows that 357 Sig max pressure is 40K. Max for 40 S&W is 35K. Could it be that 40 S&W cases are not as strong as 257 Sig?

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DEACON:  indeed, I don't have any proof there may have been an error in the charge for

those 2 rounds.

I will say that I've loaded probably 1000+ rounds for my .357 SIGs and fired them without

ever having any issues.   Matter of fact, everytime I use new load data for powder, I check

the brass for visual pressure signs.   I've never noticed any issues with this particular load.

 

On a side note, once the .357 SIG brass has about 13.0 grains of AA9 powder, it basically fills

up the allowable case area.   It basically becomes a compressed load.

This is another reason that the .40 brass with 11.7 grains may have been a compressed load.

 

..........Widder

 

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S.DAVE:   OOB has crossed my mind.   But will a striker fired pistol allow me to pull the trigger

and fire the pistol without being fully in battery?    I don't know.

The max pressure you mentioned could be the gremlin.

 

..........Widder

 

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PETE:   I think the SIG's have supported chambers.   Thats something I'll double check.

 

..........Widder

 

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7 minutes ago, Crooked River Pete, SASS 43485 said:

There have been issues with 40 S&W fired from a Glock. I could be wrong but the unsupported barrel of a glock causes a bulge that weakens the case. Where did you get the cases?

Several years ago my partner and were qualifying with our Glock 23’s using Federal Classic ammunition.

Within minutes of each other both of our guns had case blowouts. The guns functioned as designed blowing out through the magazine neither of us was hurt but the guns were sent back to Glock who replaced them, I wanted to send the rest of the ammunition back to Federal but was overruled fortunately there were no more problems  

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I'm glad you were able to still use your hand to post a range report. Glad I stick to simple stuff like BP. be careful out there.

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46 minutes ago, Widder, SASS #59054 said:

LUMPY:  as much as I could 'sense', everything felt normal it the function of the pistol.   And

I only pulled the trigger once the previous shell had ejected and the slide closed....or so I think.

In both incidents, I was not speed shooting.   Each shot was a typical, show timed shot at a target.

I will contact SIG on Monday.

 

RED:  I think there may have been too much energy for that .40 brass, which had been necked down.

 

..........Widder

 

 

If you have any rnds left ck'em in a case gauge. 

OLG 

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1:  What was the neck thickness of that reformed brass?

2:  357 SIG should use 9mm (.355) bullets, not .357

3: What is measured neck diameter of reloaded rounds and how does it compare with factory ammo neck diameter?

 

Duffield

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LUMPY:  I pulled the bullets of the last 2 rounds to measure the powder charge and bullet weights.

I'll check the brass in the case gauge.

 

DUFFIELD:  I'll check out those measurements.    They were .355 bullets.   I don't shoot any .38 or .357

ammo nor have any reloading bullets for them.   Thanks.

 

..........Widder

 

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Howdy Widder :

What was the Cartridges Over all Loaded Lenght ?

What brand of Brass, Primer ???

Your Load doesn't seem to be  Excessive ...

I would be glad to help resolve this issue, I just need more info ...

Happy Easter ...

 

Jabez Cowboy

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2 hours ago, Widder, SASS #59054 said:

 

In both incidents, I was not speed shooting.   

 

..........Widder

 

Well we don't doubt that:ph34r:.

 

Your problem is obvious if you'd just think about it a minute...you pulled the trigger too hard.

 

Glad you're OK pard. Even though a good scar is worth its weight in gold with the ladies, I'm glad you didn't get one. No telling what kind of lies you'd come up with.

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Howdy JABEZ:   OAL:  1.140 at the time of reloading.  Bullet crimp is very sufficient.

The case that blew out a portion of the head area is Federal.

The case that completely separated at the rim is Winchester.

 

Primers are Federal small pistol magnum.

I'll try to take pics tomorrow and post.

Oddly, BOTH primers were still in good shape and did not flatten or back out.

The firing pin was a good round mark with NO cratering signs.

 

QUESTION:  is it possible for some weakened brass to destruct in this manner with supported chambers?

 

Ya know Zabez, the more I think about it, the more I lean towards excessive pressures only because of

the .40 size brass and it being a little shorter than .357 SIG brass.

I just measured the piece of brass that didn't separate and it mic'd .837  

My .357 SIG brass measured .860

hmmmmmmmm.

 

As a side note,  I was shooting these particular reloads just to get rid of the .40 brass.

I only had a couple dozen of them and was going to throw away the .40 brass

after I shot em up.

 

.........Widder

 

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TN,  

I see you're still up and causing trouble at 12:30 a.m.

 

You're probably putting some super glue on easter eggs.

 

..........Widder

 

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Widder, do you think there is any way the bullets may have gotten set back in the case causing an over pressure problem? 
 

I have a Ruger PC Carbine 9mm. I was using an old Glock magazine that I had found in a bargain bin. The mag’s lips were opened up so the cartridges were not feeding at the proper angle and I had a couple bullet set backs. The bullets in the cartridges were hitting the feed ramp at too sharp of an angle. The force of the recoil was sufficient to slam the bullet back into the case yet the cartridge would still feed. 
The only indication was the first 2 rounds seemed “stout”. The 3rd round jammed the gun with the bolt open and the cartridge was stuck against the feed ramp and the bolt and the cartridge was a good 1/8th of an inch shorter.

 

Upon inspection I found the magazine lips to be spread apart too far. I cannot remember the dimensions but in comparison to new mags there was an obvious difference. 
 

 

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Hey Patriot.

I thought about the bullet moving in the case and seating deeper.   And yes, it is possible.

The main thing about dispelling that theory is that I reloaded ALL of these on a single

stage press, which allows me to 'feel' every bullet as its being seated and the taper

crimp applied with the seating die.

 

I've used the same die setting for 1000+ rounds.   Every time I reload, I take a few samples

and press the bullets hard against the table to ensure they are not moving in the brass.

I visually check em and mic those samples after pressing them against the table.

 

I would rule against bullet set back..........BUT, it is a slight possibility.

 

I might add that I also visually check my empty brass right before putting powder in them

to make sure nothing is inside each piece, like a lady bug, etc.....

And I normally only load 30 at a time in the loading tray and visually check each for powder

volume consistency before seating the bullet.

 

I've been reloading since the mid 70's.   Like many of the Pards, my reloading experience

is vast and lengthy with Smokeless powders.

I've never experienced anything such as this occurrence, which tends to make me think

it may have very well been the shorter .40 formed brass.

 

..........Widder

 

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11 hours ago, Red Gauntlet , SASS 60619 said:

There may have been too much energy for the application.

 

Captain Obvious called.  He wants his title back.  

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12 hours ago, Widder, SASS #59054 said:

PETE:   I think the SIG's have supported chambers.   Thats something I'll double check.

 

..........Widder

 

My point was not the chamber in the SIG, but the chamber in the gun that originally fired the .40 ammo. If it had been ever fired in a Glock that leaves a bulge in the case that weakens the brass. Many reloaders will not reload  .40 cases fired in a Glock because of this.

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6 minutes ago, Crooked River Pete, SASS 43485 said:

My point was not the chamber in the SIG, but the chamber in the gun that originally fired the .40 ammo. If it had been ever fired in a Glock that leaves a bulge in the case that weakens the brass. Many reloaders will not reload  .40 cases fired in a Glock because of this.

 

Now that is a point I had not considered.   That is a possibility.

 

I had gotten this 'once fired and reformed' brass from another shooter.  I have no idea as

to what 40 caliber pistol it may have originally been fired.

 

Thanks

 

..........Widder

 

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Widder - The Lyman Reloading Handbook (mine is edition #49) specifically warns against attempting to form .357 Sig brass by necking down 40 S&W cases, as they will be approximately .020" short. They also warn against using 10mm cases due to use of a large primer. Suggest you read this section carefully as there is also a bunch of caution about which bullets to use.  Bullets should be .355" diameter, not .357". Your powder charge is on the mild end of the load with the min. listed as 11.5 of AA#9, it's OK. 

 

My suggestion is to buy .357 Sig cases from Starline and to stop making due with substitutes. Also check your bullet diameter and get a Lyman manual. 

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The shorter brass in and of its self wouldn't cause over pressure. What it would cause is a weak crimp unless you reset the crimp die to account for the shorter case length..  

 

When the 40 brass was resized to .357 Sig the dimension from the base of the case neck to the base of the cartridge would be the same as it would for factory 357 sig brass.  The difference in length is in how long the neck of the case is. In theory this means the internal case volume would not be effected by the shorter case length because the distance between the base of the bullet and the base of the case is the same. This doesn't take into account any differences in the physical construction of the brass. 

 

Because the OAL of the case is shorter, when you applied a taper crimp to the cartridge it would be weaker on the reformed 40 brass than on the 357 Sig brass unless you set the crimp die specifically for the shorter case length.  Even if you did this there would still be be less neck tension as there is less bullet to neck contact..

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12 hours ago, Duffield, SASS #23454 said:

1:  What was the neck thickness of that reformed brass?

2:  357 SIG should use 9mm (.355) bullets, not .357

3: What is measured neck diameter of reloaded rounds and how does it compare with factory ammo neck diameter?

 

Duffield

I'd add to the questions with :  What is the water volume of the reformed cases versus a factory case? 

If the volume is less for the reformed cases, there may be an over pressure problem.

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1 hour ago, Sedalia Dave said:

The shorter brass in and of its self wouldn't cause over pressure. What it would cause is a weak crimp unless you reset the crimp die to account for the shorter case length..  

 

Shorter case resulting in improper crimp is my Theory #2. Bullet slides around a bit and pressures climb. But that wouldn’t explain the two episodes in one gun and not the other. 

 

13 hours ago, Duffield, SASS #23454 said:

 

1:  What was the neck thickness of that reformed brass?

 

 

Excess neck thickness was my Theory #1. Assume both guns have SAAMI spec chambers, but one is on the tight side of tolerances. Too much bullet and brass in the chamber, even by a few ten-thousandths,  and bad things happen. 

 

Glad you are safe and that this is a reloading and not a medical discussion. 

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Widder:

First off Your power charges are barely above the Recommended Starting loads and With-out Bullets being "Set-back" pressures would be on the Mild side...

I think in both instances the Brass had more firings on them than you believe... Secondly reformed .40 Short & Weak brass has slightly less volume , the shorter neck has very little bearing on pressures as long as it has enough grip on the bullet to avoid bullet movement ... 

Secondly I think the Two cases Failed for two different reasons and in two entirely different ways ...

First the Federal Brass , I strongly suspect it has been fired multiple times in unsupported Chambers , When the Sig. 357 first came out We used reformed Short & Weak Brass for pressure testing ... One Lab I am aware of had a couple of unintended Mag. releases due to bullet Set-Back with mid-range powder charges of Mid to  faster burning powders... These were deemed to be Over Pressure situations...

But they also had a number of blown heads that were traced to cases that had been fired several times in unsupported chambers , that is why the SAMMI     

regulated testing Labs Strongly caution against using reformed .40 S&W cases ... 

As an aside I find Federal .40 S&W cases to be the poorest cases in that caliber ....

In the case of the Complete case head separation of the Winchester case I suspect that this was a Well used Case probably with loads close to Max ...

The other possible cause could be cleaning brass with the Wrong chemicals causing the brass to get brittle, I have seen this Done ...

I also think that bullet Set-Back could be part of the Problem ...

Your load of 11.7 gr. of A 9 powder should have limited bullet Set-back to a degree, with-out testing I can't say that for sure but I doubt that in good brass and in your gun pressures would have caused a ruptured case ...

I have Found "Star-Line" brass to be inexpensive and Great Brass ...

I hope this Helps ...

 

Jabez Cowboy

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Widder, how many times have you loaded that brass?

I suggest you also do a chamber cast to confirm it's dimensions.

OLG 

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Powder contamination? 

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Sorry to hear what happened but glad you're ok!

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Has the brass been through a bulge buster , possibly of them being stretched their once already, I also would want to confirm the case neck thickness , if it can’t “release” the bullet , you could have pressures spike 

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My Speer manual says that the case headspaces on the case mouth, not the shoulder. Also not to use .40 brass due to this. The resized brass is too short.

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