Case split?

[Impureclient]

I had a box of older Remington 9mm ammo that I got from my grandfather that I shot a while ago. It was the first time I had shot the new gun also.
I collected most of the casings and I noticed that a few of them were splitting lengthwise. They are split enough that you can see light through them.
Is that normal with older ammo? I havent noticed it on any of the new stuff.

 

[Hk Dan]

Well, that end of the case is annealed (softened, made flexible) to seal the chamber. Usually when cases have been stetched and re-sized enough times, you see it. I've never seen a modern gun with a chamber so out of spec that the cases split on the first shot, though.

Are ya sure they aren't reloads?

Dan

 

[Chester32141]

I recently had a brick of .22lr that was about 30 years old that split about 50% of the cases in four different guns ... I know they were stored properly because the other bricks shot were fine ... 2 of the four guns were new so I don't think the chambers were the problem ... no way of telling if they had been fired when new if they would have split ... I believe the brass just got old ...

Chester

 

[Impureclient]

I forgot to add they were split in the middle and didn't rip all the way through the end where the bullet is crimped in.
They very well may have been reloads and just boxed in the brand name box as he had tons of other reloads with
what I got.
There must have been about 60-70 lbs. of assorted ammo. 9mm, .38, .44, .45, .357, .22, .25, .32, a few
others and some rifle caliber. We took it to an outdoor range and shot almost all of it in one sitting except the rifle rounds.
That was a fun day. Even my 10 yr old son was shooting the bigger stuff and he had a blast.
Back to topic: I guess it was just old brass. I didn't know it got weaker with time as people talk about shooting ammo left
over from the W.W.s and don't have problems. I did notice this stuff was extra stinky and dirty also. Nothing like the newer stuff.

 

[230RN]

Are you sure you weren't firing 9 mm Corto (.380 ACP) or the Largo cartridge in a true 9mm Luger gun?

There's only about .007" difference in the neck diameters of .380 ACP versus 9MM, but a large-ish chamber combined with a smallish sizing die, or using .380 dies for loading 9mm cartridges might account for the splits. And there's a .011" difference in the diameters back at the head.

.380 ACP will fire in a Luger if the cartridges are fed up from the magazine, where the extractor claw can hold the head of the case back to the breech so the firing pin can hit the primer.

Also, Hatcher notes several instances of what he calls "season cracking" in improperly annealed or formed cases, but I don't have the references right now.

Just guessin'.

Terry, 230RN

 

[Sheldon J]

What he said... chamber variance would be a good explanation for this...

 

[Impureclient]

Nope...I just looked at one of the spent casings. It says 9mm luger.

Probably just because they were old I guess.

 

[230RN]

OK, I'm just thinking if it wasn't season cracking, they might have been reloaded in .380 dies or actually have been .380s --which apparently they were not.

I sure wouldn't mind a guess at the OD of the fired cases, if you have a mike or calipers handy.