It can be loaded with inert rounds, the barrel revolves with the trigger but the hammer is deactivated.
I believe the B prefix indicates it was manufacured from 1957 through the 1960's. Most likely a police revolver as it has the safety catch that isn't present on military spec revolvers.
I'm selling this as i want to collect WW1 related items so i'm after a .455 or similar from that period.
Price includes UK postage.