Ok, time to solve it.
It is a Russian TZP-3M torpedo engine starter cartridge for the 53-65V torpedo.
Dave, you'll decide who shall keep on.
I mentioned Torpedoes back on Nov. 23. A "Yes one of those" would have been a help.
Can't believe nobody got that one.
Thanks Dave!
You will eventually like this one.
Sorry I didn't have a larger photo.