Originally Posted By: Roundsworth
The 'UMC' headstamp is pre-1912ish. The nickeled primer would be post 1926-ish, after the development of non-corrosive priming. I doubt it is factory loaded. Value is hard to determine for cartridges, but, someone may be interested in it for its uniqueness.

Thanks Chief (USN-CPO) Roundsworth, and others, for those details. Makes good sense.
I suspect more of a conversation piece than anything else. Sure wouldn't recommend shooting it.
Jolly