Shell casing?

[ALAMOTX]

How old is this shell casing and what does the U mean?

I have found lots of these in this town from 1852.

Thanks

 

[snake35]

Looks like a .41 Remington derringer casing.

 

[traderoftreasures]

Looks like a .41 Remington derringer casing.

right on

 

[NHBandit]

Probably Union Metallic Cartridge Co. There's a great website that has a ton of different headstamps from the US as well as several foreign countries. The best site I've found for identifying ammo. http://cartridgecollectors.org/headstampcodes.htm Everyone who finds brass shell casings and wonders where they came from should have this saved to their favorites..