This splendid device was sourced in a shop on Scarborough last month. It is a diecast piece complete with a (quite long range!) firing mechanism. The calibre of the gun is 5mm, so even very large matchsticks could be fired. I have no idea of it's origins but cast on the left side are the words "ABULLOCK GUN" - with the spacing as per my typing. To give an idea of the size of the thing it is posed with a pair of Starlux French officers (above) and a Conte Confederate officer (below).a Bullock Long Range Coastal Gun by MSR Toys: http://www.liveauctioneers.com/item/2114775
Thanks again Alex!