Ah, USPS? I know, smart azz reponse, but I was not aware of any restrictions on shipping such items outside of the US. You should be able to send it anywhere UPS/FedEx/USPS ships.
If you are outside of the US trying to order it from Crossman, they may just not want the hassle of shipping overseas or the risk of overseas payments being stopped w/out recourse or protections for them.
In life, strive to take the high road....It offers a better field of fire.
"Robo is right" Fuzzball