Copper bottle PIC ADDED

[Captain J]

I need help Identifying what appears to be a copper bottle. Sorry no pick.

Anyways, its about the size of a 750 ml bottle. Aprox 3" dia
About the same weight (empty) as a full 750 ml bottle.
No markings, no seems.
Has a screw-on cap with the male threads on the cap.
The cap also has 2 small holes on each side.
bottom is concave.

If anyone has any Ideas, please throw them out there. Even a wild guess would be apreciated. Is there a distinctive use for metal bottles?

Thanx in advance

EDIT: PICS ADDED

[Kentucky Kache]

Thermos?

[Captain J]

Thermos?

I was thinking kinda along those lines, like some sort of canteen.
I should have mentioned the opening is only about 3/4"

I just can't get anywhere on it as there are 0 markings.

[treasurekidd]

Just a crazy guess, but could it be a powder flask? I've seen a few antique copper and brass gun powder flasks that sound somewhat similar to your description.

[Captain J]

bump- pics added to OP

[Gypsy Heart]

Could it be a type of hotwater bottle

[Zym]

I don't think it would be a thermos, copper conducts heat to well an doesn't insulate. A hot water bottle sounds more plausible IMHO.

[tulecanyon]

it is a powder flask. the giveaway is the thumb operated latch.