The WW1 US 1.457 inch Sub-Calibre shell casing i have is it seems even paining the experts as the case dimensions and construction of this one is different to nearly all others encountered. The case is 142mm long (deffinately not 145mm) and has an unusual belt, not a deformity caused by some sort of fault as i had thought. I also thought this case had a central screw in type primer but i was wrong as no threads in the small primer hole. Headstampings are as follows: L 3063 1.457 In Subcal Gun, FA 1915. There is also a kind of fork shaped symbol. Might this have been some form of experimental 37mm????? Would like some ideas as every case i have seen of this type has no case belt yet mine does??? Regards, Tim.