Very nice Rigby 275. Its very similar to my Rigby High Velocity .275, Rigby number #5382 with a military action and bolt. Mine has the original scope mounts on it (they are the traditional Rigby mounts with the quick detach lever on the front mount). Mine dates from 1932 and if I only had a copy of the next page of the Rigby ledger it would most likely have your rifle on it. You might contact Paul Roberts at "J. Roberts and Sons" to see if they can provide you with a scan of the page with your rifle in it. I'm pretty sure that they have the correct ledger with your gun in it as I physically copied this page from the ledger when I toured the shop in 2005. Is your rifle a High Velocity model (140gr bullet)?