Pete, John has the best solution, if the Luger is intact the law requires it to go FEDEX overnight air. If you disable it, ie; remove critical parts like the trigger, firing pin, etc. it is no longer a functioning weapon and you can send it by regular ground delivery ( much cheaper) by UPS or FEDEX. Plan ahead and have you shipping container and packing material with you, pre-addressed to yourself and then just take it to the shipper and you're ready to go. Here is come info on FEDEX and UPS policies-
http://www.seark.net/~jlove/shipping.htm