TL, The best way to ship is U.S. Postal Service. I've done so half a dozen times at this point with no problems.
You package the gun. I use a hard case with thick wrapping paper around the case. You seal it with the special gummed tape that has reinforcing fibers in it; you have to wet the tape to make the gum/glue active. You must use that tape in order to register the package. Check the tape out at your local branch post office to be sure you get the right stuff.
Take the wrapped and addressed package into your post office and get the insurance form (Do not/not use the form for $200 max for your Purdey!!!). Insure for the value of the gun that you can justify using a bill of sale or an appraisal if you've had it many years and it has appreciated. Do NOT tell the postal clerk what is in the package. Your fees will include postage, registration fee and insurance.
Regards, Tim
Last edited by Tim Carney; 02/20/13 11:22 PM. Reason: added point