There are private sellers who have an unrealistic idea what their gun is worth, so they consign it to someone who just throws it up on GB, rather than work out a reasonable expectation with the seller. The GB seller's name sort of suggests he's not principally a gun dealer. "Promotions"?

There are plenty of sellers online who seem to be running an online museum rather than be serious about selling guns. Some have been on for years at the same unreasonable prices