Don, FFL dealer for shipping. FedEx requires a license to ship firearms. I would ask Buds if they will send a return ship box at 1-859-368-0371 9am-9pm EST Mon-Fri. or use the Blue Chat now button at the bottom right corner 9am to 9pm Mon-Sat and 11am - 7pm Sun (7 days a week).

Unless by "gun" you mean a shotgun or rifle which is unloaded it can be sent to an FFL or another resident in your same state as explained here (ATF.gov): https://bit.ly/2Geebyf otherwise I agree with James from everything I looked up and my experience the only way unless you are mailing for repairs to the manufacturer in a return shipping box sent from the manufacturer is to go through an FFL that would be able to ensure that it is being sent to another FFL. Its better to be safe than sorry anytime you are sending a firearm.

In general, An individual (Non-licensee) is legally authorized to ship a firearm to an FFL/FFL Dealer. The firearm must ship by a contract carrier (FedEx / UPS). My experience has been FedEx is much easier to deal with in general. You must include contact information (I enclose a copy of my driver license) inside the packageand you must declare the firearm at the time of shipping (to the FedEx Rep). The firearm has to be securely packed/packaged, with nothing on the exterior of the box/package indicating what is inside. It must be shipped "express", (not ground) and shipped to require adult signature upon delivery. Insurance is strongly recommended (if carries does not automatically provide with shipping fees). Receiving FFL will sign for the firearm, and if it is to be transferred to another individual, will perform the transfer in accordance with the law. If you are shipping to Buds for a trade-in, then, yes, contact them for guidance and assistance prior to shipping. Please investigate for yourself and become comfortable that you are within the law before ever shipping a firearm. There are exceptions to this information is specific cases which require specific individual guidance. But, yes, an individual can legally ship a firearm to a FFL holder, in compliance with the carrier's requirements.

must be sent by FFL dealer

must be sent by FFL dealer