40mm/1.5inch Shell

I have what appears to be a 40mm/1.5inch shell casing.
It’s a bottlenecked centrefire and has a live primer but no projectile or charge.
It’s dimensions are:
Neck Dia : Approximately 1.5" Inside (Out of round)
Length : 4.700"
Base Dia : 1.640"
Rim Dia : 1.895"
Shoulder Dia : 1.58" at 3.70" from rim.

Headstamp: Manufactured by Winchester Repeating Arms Co. New Haven Conn. USA
B in a circle with flames or leaves out the top.
Anyone know what it is/was? Was this a grenade or a shell?

pretty sure the casing is a 37mm hotchkiss

It is a 37x120R Hotchkiss Winchester Navy


Thanks for the identification. I don’t have any info on large ordnance and just searching on the web I’m finding a lot of references to 37mm Hotchkiss shells in general but not the 37 x 120R. Was the 37 x 120R fairly common? What countries used it. Being a Navy load can I assume it was for anti-aircraft use? Also is the 5-91 a date code or load ID?


I’m not positive about the “B in a circle with flames or leaves out the top”. Some US Army ordnance will have the “flaming bomb” that is part of the Ordnance Department emblem. Most will have the entire emblem. This usually is only present on Army ordnance and not Navy which is marked with an anchor.


The “5-91” is the date of manufacture of the case, May, 1891.

I don’t think it’s the ordnance dept. symbol as the “leaves” appear to spread outward like a pineapple rather than in like a flame. I’ll take another look tonight.