Q5. I wish to buy ‘prohibited’ firearms or parts in the US and import them into Canada.
A5. The importation of ‘prohibited’ goods is strictly controlled by Canadian legislation. The import of prohibited firearms may only be undertaken by businesses with a Canadian Firearms Business Licence which supply such firearms to the police, military or theatrical/cinematic industries. For more information on import eligibility contact International Trade Canada or your Chief Firearms Officer. The import of parts for prohibited firearms is controlled by the “Export and Import Permits Act” (EIPA) and an Import Permit is required. This is in addition to the IIC which may be required by the exporting country. The import of parts for prohibited firearms may require proof that the importer is a ‘grand-fathered’ owner of the firearms in question and that the imported parts are to maintain the prohibited firearm in a safe condition.
http://www.international.gc.ca/eicb/military/faq-en.asp#4