odd barrel marking ?

I have just seen a 1902 carbine with "(JVM)" stamped on the underside of the barrel. No other proofs, marks, or numbers are visiable on the barrel. The barrel and extension are in much better shape than the remainder of the gun, suggesting a rework but the stamp is clean and untouched. Any ideas on what these marks mean.


Also, in my experience, carbine parts are stamped with the last three digits of the serial number, but this gun has only the last two digits. ???


Any ideas would be very welcome... FGR