What happened to this cartridge?


#1

The picture is not the best but I hope you can see the indents in this cartridge(.22 Mag rimfire). It looks like it was subjected to some great pressure or something but it was in a drawer (my drawer) in the mountains, over the winter, with five others and only one came out like this. The only thing that happened, that I know of, is that the temperature got down to below freezing, near zero.

Speculations?


#2

Shotmeister,

Very curious. The drop in temperature could cause the pressure in the sealed cartridge’s interior to be below that of the atmosphere around its outside. As the powder and air inside thermally contract, no air can be drawn in to replace the lost volume. This assumes the case doesn’t contract as much to offset the volume change of the contents. BUT… the maximum this pressure differential can be is around 14.7 PSI (maybe lower in the mountains!) if somehow you pulled a perfect vacuum in the interior and I don’t think even that much pressure could cause a .22 WMR case of proper thickness to buckle in like that. Putting a few in the freezer to see what happens would do the same as a cold winter night.

Would have to guess some other forces (aggressive centerfires?!?) were at work here!

Dave


#3

I would have thought a pressure effect would have been more uniform rather than localised like those marks. Its not been carried in a pocket with a big bunch of keys or anything similar? Or carried in the trunk of a car with a rifle (camera etc) on top of it over over bad mountain roads? Those cases are thin and dent easily.

Could be the squirrels have been using it for football practice. Squirrels have no respect for other people’s property.


#4

As Dave suggested, I put a couple of similar cartridges in the freezer for several weeks then removed them to room temp. The only change was a purpleish stain around the bullet itself, no change to the case.

In fairness, I placed one on a flat location in the yard where squirrels like to eat acorns but to date they haven’t used it for football practice or anything. But since a squirrel was unlikely to have fit in the drawer originaly mentioned, I think we can rule them out anyway. Just trying to be scientific about this.

Would anyone else like to venture a viable explanation to what happened to this .22 RF round?


#5

It would be interesting to see the inside of the cartridge to see if there has been any form of chemical reaction which is changing some of the brass regions and not others. I doubt very much air pressure could cause this but pressure between rounds rubbing in a pocket could cause the semicircular dents. Just my 2 cents, besides if it cost 1 penny for your thoughts what is the other penny needed for? Vic


#6

Oh boy, this has a feeling of deja vu.
I would say they are dents. I feel than anything pressure or temperature related would have acted over the whole surface area evenly and sucked it in like a coke bottle. Beyond that I don’t know.

Maybe it happened during manufacture. A round that got dropped on the floor and trodden on before before being picked up and dropped back into the bin. Or a packing machine jam up or something of the sort.


#7

[quote=“Shotmeister”]… it was in a drawer (my drawer) in the mountains, over the winter, with five others and only one came out like this. The only thing that happened, that I know of, is that the temperature got down to below freezing, near zero.
[/quote]

I took these cartridges out of revolver and put them in the drawer. There were 6 but only one came out like this. It will not fit in the revolver, or any other chamber, now. It was not carried in a pocket or anywhere else, at least in the period this damage occurred. Since I can’t shoot it and I’m not going to cut into a rimfire, I guess I’ll never know what happened. So I’ll just file it in my collection as “The Great Mystery” and maybe I’ll put it on my table at SLICS next year for genereal conversation.