9mm case blowout

[CLT65]

I know a guy who had an incident with a hand grenade in the military. He is missing an arm and an eye.

 

[pencap]

If you don't personally chrono your rounds, you really have no idea what is happening in your particular gun.

9mm (.40 especially) is on the steep section of the pressure-volume curve. That is to say with a particular charge of powder, if the case volume (OAL) varies AFTER the round has made it up the ramp and into the chamber, you will get high pressure signs, greatly variable velocity, and blowouts.

Buy a chrony and check your crimp.

 

[best defense]

After reloading thousands of 9mm it finally happened case blowout.
10 rounds loaded and on round 6 all I saw was a blast of white smoke and a quick sense of heat on my finger, but to make matters worse as I saw the smoke my vision blurred and it hit me... my safety glasses were on my hat instead of shielding my eyes.
After hobbling to the cars side mirrors to check for damage to my face which luckily there was none (with vision fading I feared the worst) I went back to the pistol that I set on the ground facing the burm.
The gun a beretta 92fs went through the case failure with no apparent damage I pulled the gun apart and no cracks, extractor intact, no barrel bulge and it even kicked the case out and fed a fresh round like nothing happened.
Interesting enough this wasn't from some hot rod Blue Dot load but instead a mild charge of Bullseye. Working up a load for 124gr jhp carefully scaled with the start load at 4.1grs and the ceiling being 4.3grs.
The blowout occurred with 4.2grs with a jhp seated at 1.060 which I have seated that exact same bullet at that depth with HS6 with zero problems.
Everyone had packed up and left the range so had I been blinded by this event I would have had to try and find my way to the nearest road in thick fog after unlocking a gate.
I had been wearing my glasses this entire session but for some reason when I went back to the bench and loaded the magazine I took my glasses off and set them on top of my hat.
The twenty foot walk to the car was like an eternity not knowing if I'm in shock and have suffered head trauma or if there's a laceration that I can't see. I dont know how I got so lucky that aside from a burn from venting gasses on my finger was the only damage today and even the guns plastic grips didn't crack and the magazine didn't eject.
Ladies and gentlemen I joked on the forum regarding safety glasses but this little incident has 100% changed my views on protective gear as eyes and many other body parts are irreplaceable and that walk to the car is not something I ever want to do again.
Be safe, have fun shooting, and dont get complacent like me...

View attachment 542516 View attachment 542517 View attachment 542518

*************************************************************
Is it possible that you might have double charged that case?

 

[The Courier]

*************************************************************
Is it possible that you might have double charged that case?

No chance, all cases were individually weighed and visually inspected before loading. And I am OCD about zeroing and calibrating my scale before each session.

 

[ConcernedCitizen]

That line looks way too clean. It looks to me like a case head failure, but not a true case head rupture caused by overpressure.

 

[The Courier]

If you don't personally chrono your rounds, you really have no idea what is happening in your particular gun.

9mm (.40 especially) is on the steep section of the pressure-volume curve. That is to say with a particular charge of powder, if the case volume (OAL) varies AFTER the round has made it up the ramp and into the chamber, you will get high pressure signs, greatly variable velocity, and blowouts.

Buy a chrony and check your crimp.

I have a chronograph and I do check my crimp.
I spend most of my free time researching loading data and different techniques, I also press checked every round in the berettas chamber to ensure all would fit and drop free.
Next weekend I will check velocity vs Nato spec ammo.

 

[pencap]

Measure 5 or 10 rounds OAL then manually feed them (drop the slide, don't ride it forward), eject the round and measure again.

If the rounds shorten a little on their way into the chamber but are still long enough to complete the feeding process they can detonate with much higher pressures because the case volume at the point of detonation is less.

 

[DizzyJ]

Measure 5 or 10 rounds OAL then manually feed them (drop the slide, don't ride it forward), eject the round and measure again.

If the rounds shorten a little on their way into the chamber but are still long enough to complete the feeding process they can detonate with much higher pressures because the case volume at the point of detonation is less.

Funny you say that. A few years ago I loaded up some "light" 122gr lead rounds for USPSA and 3-gun. While I noticed no difference in the Beretta, when I chambered and fired them in the Walther, it was a VERY noticeable increase in recoil!

Come to find out, the shoulder on the bullet was jamming into the lands and greatly increasing the pressure! Recoil was significantly more than the fmjs I run!

Lesson learned!

 

[ConcernedCitizen]

I had to plunk test all of my different barrels, and settle on a shorter OAL that worked for all of them.

The Glocks have a pretty generous throat, but my XD has a rather short leade, and required me to seat the bullets deeper than I had anticipated. The profile or ogive of the bullet also makes a big difference in COAL, with truncated cones needing to be seated much deeper than round nose bullets.

 

[The Courier]

I had to plunk test all of my different barrels, and settle on a shorter OAL that worked for all of them.

The Glocks have a pretty generous throat, but my XD has a rather short leade, and required me to seat the bullets deeper than I had anticipated. The profile or ogive of the bullet also makes a big difference in COAL, with truncated cones needing to be seated much deeper than round nose bullets.

Yep, the wife's XDS requires a much shorter COAL which is kind of a bummer.
The bullets are a round nose profile JHP so I could load them longer for the 92fs but if I don't want two different bullet lengths my maximum COAL 1.065 for the XDS.
This was the main reason for selling my CZ75 as what worked for every other pistol would not chamber properly in the CZ.

 

[ConcernedCitizen]

Yep, the wife's XDS requires a much shorter COAL which is kind of a bummer.
The bullets are a round nose profile JHP so I could load them longer for the 92fs but if I don't want two different bullet lengths my maximum COAL 1.065 for the XDS.
This was the main reason for selling my CZ75 as what worked for every other pistol would not chamber properly in the CZ.

I believe my Precision Delta 124gr JHPs were 1.080". Surprisingly they are still very accurate out of the Glocks, despite the long jump to the rifling.

 

[mmaton]

Had the same experience about a week ago. I think there's something up with the Winchester brass. 4.6 grain of titegroup 1.130 OAL barely any crimp with a FMJ 115grain projectile out of a glock 19

 

[The Courier]

Finally got out to the range after being sick kinda delayed chrono testing.
Here is the results.
Bullseye 4.2grs FPS 1039,1051,1040,1048
Bullseye 4.3grs FPS 1058,1061,1052,1047

Now I decided to ditch this load and switch to Unique and I was very pleased with velocity and accuracy.
Unique 5.5grs FPS 1144, 1161, 1164, 1144
Unique 5.6grs FPS 1164, 1181, 1154, 1177
Unique 5.7grs FPS 1140,1150, 1164, Error.
Bullseye primers below.
Unique primers below.

And the targets for the Unique load, I think I've settled on the 5.6gr load as group was at 1.5" and 5.7grs did not seem to promise increased velocity and the group was so-so.