A Rigby Mauser in .275 Rigby aka 7x57 rifle offered for sale on egun: http://www.egunner.de/market/item.php?id=4599625
According to the seller bought in the early 1990s from Rigby, then still London, Paul Roberts era. Receiver ring inscribed : Sighted for Rigby's spezial High Velocity 275 bore cartridge pointed bullet 140 gns . Mounted with a 1960s Hensold/Zeiss West 4x32 Diasta D scope on a German EAW side mount.
Apparently heavily reworked, refinished and recheckered. The bolt handle at least is a replacement IMHO, as it has a round military knob, not the teardrop shape of the advertized "last before WW1" time. The cocking piece is also a replacement, as it is the short military type. asking price: Euro 4400.-, about $ 5940.-