If you have a gun to sell, antique, modern, handgun or rifle, you will need to be familiar with your state and local laws to sell and transfer ownership of a firearm. Some states have very strict registration requirements, other states require next to nothing for a sell between private parties. here are the steps in selling your gun. It is easiest to sell in state. If you sell across state lines you will need to work with a licensed dealer in the state the new owner will be in and abide by those laws.
Check into selling the gun to a licensed dealer in your state. Local sporting goods stores and pawn brokers often are licensed to deal in firearms. You can sell to them directly or let them sell for you on consignment. They will take care of any required background check or waiting period necessary. Licensed dealers can also let you know local requirements for selling the gun yourself.
Contact local law enforcement. If the gun is registered to you, you may need to fill out a form and transfer registration to the new owner. This may require a fee, but will insure if the gun is used in a crime, or later stolen, that the gun is not still registered in your name and place you in the position of being a crime suspect.
Check out local gun shows. You may be able to rent a table and sell at a show if you have enough guns to make it worth doing, or sell to a dealer or through a dealer at the show. Show dealers are usually very knowledgeable and familiar with current prices. Gun shows also attract many buyers. You may get a higher price than you would selling in such a crowd.
Get the name and a copy of the drivers license of the party you sell to at a minimum. Make sure you have a buyer that is of age. I personally sell through licensed gun dealers for any handguns so a background check gets done for my own peace of mind. Hunting rifles I will often sell directly through a classified ad, but I will get the information of the person I sold it to and store that in my safe. I also will not sell to anyone I don't feel personally comfortable with.
If selling through a classified ad list your cell phone number, but never your address. You don't want to be a target for theft. Use a cell phone number instead of your home phone so you are not searched as easily in a reverse phone directory for you address. I recommend meeting a potential buyer at a local gun club or shooting range. This will never be a problem for a legitimate buyer. If someone is looking for an address with guns to steal they will not show up.