This from the resident 37mm expert over on BOCN.
[i]Generally attributed to the Johnston Seckendorf Co in NY City.
Usually 37x136, but you appear to have a 37x145 subcal case marked by them, this is unusual. Any nickel plated projectile will do, they stuffed anything into them. [/i]
And this from another member…
The mystery mark. Found on souvenir make up of surplus cases afterWW1. can have inscriptions or soldered on bits. Should be 136mm long, but who knows might have been available then frmn the surplus of the factories. Maybe untrimmed