Here's a riddle for sale. A octagon barrelled Mauser http://www.egun.de/market/item.php?id=1483962
marked "Charles Lancester 7 Bury Street London England ---For 256 Mauser Cartridge". I suppose this refers to the 6.5X57 Mauser. Does the address reveal the date of manufacture, or was Lancaster there too long for the address to be significant?

The rifle is for sale on consignment, and the seller doesn't even know how to spell "white hunter". He has several other putative African rifles for sale, all with the same misspelling.

He says he is open to offers as long as no bids have been made.