Case bulge (blowout)

[Blanco]

Was at the range yesterday. Took my son(25) along for the fun.
I was testing some loads for my S&W Shield (40).
When I was loading he was shooting my Beretta 96(.40 )
He was shooting some of my reloads that are pretty middle of the road ish.
he got my attention and said he was having several rounds not going off, and when they did they were not ejecting.
I watched him shoot a couple of rounds and caught one of the pieces of brass being ejected.
The case neck was bulged considerably, as big if not bigger than .45. I stopped him and told him to stop shooting and I brought the remainder home.
After thinking about this it hits me as very strange. For the neck to bulge like it did the brass would be in motion while the bullet was still under considerable pressure, almost like a timing issue or even an over crimp?

Help me out here I have never run across this.
The load is I think 5.5 Gr. Unique with a Berry's 156 Gr Plated TC.
Nothing special that I can think of ?

[C.F.Plinker]

I have one case similar to what you are describing. Someone fired a .40 in a 45ACP pistol. Can you post a picture of the piece of brass you saved?

[gtgeorge]

Wow that is strange. Sure they weren't being shot in a 45? I will be watching this thread as I don't understand how that would be possible.

[USAFrox]

I just had an issue with FC brass in two of my .40s. Tore two of the case heads off and broke my extractor. No pressure signs (flattened primers, etc), but looking in the fired cases, the stinking brass shows tears inside, right around the flash hole like they're all getting ready to lose their case heads. Bad (weak) batch of brass. Was it FC brass, by chance?

[Char-Gar]

Was at the range yesterday. Took my son(25) along for the fun.
I was testing some loads for my S&W Shield (40).
When I was loading he was shooting my Beretta 96(.40 )
He was shooting some of my reloads that are pretty middle of the road ish.
he got my attention and said he was having several rounds not going off, and when they did they were not ejecting.
I watched him shoot a couple of rounds and caught one of the pieces of brass being ejected.
The case neck was bulged considerably, as big if not bigger than .45. I stopped him and told him to stop shooting and I brought the remainder home.
After thinking about this it hits me as very strange. For the neck to bulge like it did the brass would be in motion while the bullet was still under considerable pressure, almost like a timing issue or even an over crimp?

Help me out here I have never run across this.
The load is I think 5.5 Gr. Unique with a Berry's 156 Gr Plated TC.
Nothing special that I can think of ?

You "think" the powder charge is 5.5 grains of Unique? Don't you keep records? Start breaking down those loads and weighing the charges and pretty soon you will find the problem, you betcha.

The autopistol has lots of moving parts and they are all designed to work in a certain sequences propelled by the pressure of the load. There is a fairly narrow range of pressure where things work as designed. Go above or below this pressure window and all sorts of funky things can happen.

[petroid]

Any chance rifle primers were used by mistake instead of pistol primers? This could explain the failure to fire on some rounds if the firing pin doesn't have enough power for the harder primers. And if the primer is hotter could cause over pressure and who knows what else...

[35remington]

Pictures would clear things up. Anything less and we're all guessing.

And just wait.....we'll have some savant claim "out of battery" before you can say "internet misinformation."

[USAFrox]

I bet it was firing out of battery... Oh, wait. Never mind.

[jblee10]

5.5 grains seems light. I would pull some and make sure. And make sure what you used for a primer. And check your bullet seating depth. Make sure the bullet is not touching the leade, it needs a running start.
But my guess would be that increasing the powder charge may take care of your problem. I've found auto loader like loads near factory levels. I'm thinking the primer is forcing the bullet into the leade before igniting the main powder charge. Causing a spike in pressure or throwing off the timing of the whole event.

[leeggen]

Now wait a minute, op said the NECK was bulged. That sounds more like a 9mm fired in a 40. For the neck to bulge the chamber would have to be swelled out as if a stuck round in the end of the barrel just ahead of the chamber.
hummmmmmm this is interesting.
CD

[Menner]

Sm rifle primers should not be the problem that is all I use for my 40's and have run them through several pistols Taurus 740, Hi Power, S&W Shield, XD, Glock and have had zero problems with FTF.

[Drdarrin]

Your brass look anything like this?
This is a 9mm casings fired in a 40 S&W.

[jblee10]

I should read closer. Neck bulge! I was thinking case head bulge. Disregard my previous post, and check your ammo supply. It's not hard to get confused and start stuffing a magazine with the wrong caliber.

[MtGun44]

That picture is of a .40 fired in a .45 chamber, or a 9mm fired in a
.40 chamber, and if the "neck bulge" looks like this . . . . well, we
know what causes it. I have found brass on the range like that, but
never have done it. Perhaps the lack of a .40 cal is my best reason!

NOT very accurate, I would expect.

Bill

[captaint]

Blanco - you might mic that case neck. If it's around .470some, we must ask. Do they make that model pistol in 45ACP ??
Sure looks like what Bill said. And, do you own one in 45ACP ??

[fredj338]

None of he aforementioned reloading issues can cause what you describe. Check the head stamp, it's likely a 9mm mixed into your ammo.

[leeggen]

Blanco let us know which of our wags is right, so we don't get the same thing.
CD