As things were quiet here after Christmas I dug out my copy of Kelly's Handbook to the Titled, Landed and Official Classes 1905 (always a good read, 1600 pages) and skimmed through all the entries for people with the initials K. de B. C.

I did not find any matches. However the initial K. for a Christian name is very rare, and the only name that fits for this period in Britain is Kenneth.

The initial de B. will probably relate to the surname of some distant ancestor. The main candidate is de Burgh, which seems to be an Irish name.

Otherwise not much help. You can always just call it "Kenneth's gun" ...

HB