Northwest Dive Club

NWDC Hive Mind, we need your help.

We keep pulling up goofy things from Port Townsend Bay. The last dive included this spent 50cal casing that appears to have blown up!

The question is, under what circumstances would a cartridge blow up like this, where the casing is expanding outward? Does that imply that the whole barrel of the gun blew too?

That was probably a bad day for someone.

My guess is that this damage pattern would also have required damage to the gun itself. If the firing chamber remained intact, the brass casing would not have had any place to blow out like that.

How would it get out of the chamber all expanded like that?

Probably split the chamber and burst the breech end of the barrel... Someone could've picked it out of the wreckage or it may have 'escaped' on its own if the whole thing blew apart...

With the struck primer, maybe it was a misfire that later burst in a fire? Hangfire that burst after extraction?

After a closer look I am sure that this cartridge did not explode. One of the signs we watch for while reloading is flattened primers. This primer is not flattened.
http://www.larrywillis.com/pressure_signs.html