Firearm's Transfer Laws and Regs

This should give you some idea what to expect, depending on where the transaction occurs. As you can see, it is still relatively easy in this country to buy and sell firearms through non-commercial means.

I've always preferred to sell through a legitimate retailer via consignment. You have a captive market, and your privacy is preserved. You also stand a far better chance of keeping the firearm out of the hands of malfeasants.