Years ago I worked for a catalog retailer called Damark that sold "Refurbished" electronics. When I checked into what this meant, it could be one of 2 things. The first reality was that these were basically new items that the customer used for a very short time and returned them for one of many reasons, wife was against it, did not like the color, too small, etc.
The next definition was an item that was well used and had important parts replaced/checked to make them functional for resale. Some of the VCRs looked like they had been dragged by a truck on a dirt road, yet they were advertised as operational.
Having owned numerous air guns, I have often been dissapointed with some of those, decided to keep them as they were cheap and worked to some extent. I should have returned several of them for a refund/exchange. I also worked in hard salvage for a retailer called Fred Meyer in 1991, they had a generous return policy on bicycles, some kids would run them hard for a year, break something and the parents would return them for a refund. My job was to break them down for scrap metal. Sears used to be like that with lawn mowers, buy it for the Summer and return it in the Fall for a refund. Damark is out of business, and Sears charges a users fee if the item is brought back used.
I would look the refurbed pellet gun over well, could be the previous owner bought it, got it home and decided he wanted something else and returned it the next day. Or....?