37mm case ID?

[navyman]

Hello all,
I've put this Trench Art Lantern restoration on a different thread before but haven't asked if anyone could tell me about the headstamp, or projectile.
It's not possible to see the primer as it has been soldered over in order to make the lamp paraffin proof! The headstamp reads; U.M.C. Co, 5-15, (May 1915?), two adjacent diamonds, and L2.
These are difficult to see as the base has been filed flat so it will stand safely.
The projectile has the melted remains of a brass base primer/fill plug which measures 127.28mm / 5.01 inches. I doubt if it can be identified but would like to hear anyones ideas?
Best regards,
navyman.

 

[pedro]

http://www.specialistauctions.com/auctiondetails.php?id=1291124
37mm (1pr) similar types were in use in Europe and UK.
Union Metallic Cartridge Company later bought by Remington

 

[Gspragge]

I have an example in 37x136 size, these seem to turn up in Europe but the exact projectile for them is unknown, it could be a subcaliber longer projectile or the regular U.S. 1 Pr kind made by any one for export. Who was using these U.S. guns at the tine is also unclear though I have a German image of two captured examples but that is also vague on who where and when.