No need for an FFL for that. If it's a long gun, you're free to use Parcel Post, UPS, Federal Express, etc. If it's a handgun, then you're barred from using Parcel Post unless it's going FFL to FFL. Federal Express and UPS require handguns to go next day service. Pack the gun securely and declare it if you're wanting insurance. Make no markings on the exterior of the box indicating that it's a firearm. Occasionally UPS and Federal Express counter dickheads will try to tell you the law and open and inspect the package. Nothing to prevent them from opening the package, but don't let them try and intimidate you into thinking what you're doing is illegal. Ask for a supervisor and the trouble will cease. If going Parcel Post, write out a short statement to the effect of "Postmaster- Enclosed is a Model XXX shotgun/rifle in XXX caliber/XXX gauge. It is being sent to blah blah blah, a gunsmith/the manufacturer for repair. I declare that is unloaded and that there are no live munitions contained herein. Signed, ME." Insure it for whatever value you think is reasonable and be on your way.