re-shipping 106mm mount from continental USA

[Roger Lucy]

Hanno is right, the export of even a de-milled reckless rifle from the USA would fall under the US State Department's International Trafficking in Arms Regulations (ITARs) which captures the export of all military goods and technology from the USA no matter how small or ancient, see http://www.pmddtc.state.gov/index.html
It's a bureaucratic nightmare that most small dealers would rather avoid
Also because what you seek is part of an artillery piece your own government probably would expect you to obtain an import permit.