In re-reading that section of Numrich's website it looks like I was confused. They talk about "up to $500" which would seem to indicate that they do ship firearms parts to Canada.
It is confusing though......not the clearest set of rules.
GOVERNMENT RESTRICTIONS
The United States Government has export restrictions in place for items such as barrels, barrel blanks, cylinders, receivers, frames, bolts, high capacity magazines (over 10 rounds), shotgun magazines, shotgun magazine extension tubes, shotgun complete trigger mechanisms, scopes etc. Additionally, we have company restrictions in place for the following common items: solvents, flashhiders, suppressors, muzzle brakes, speed loaders, bipods, monopods, gas masks, and flare pistols.
We will not ship ANY parts for ANY fully automatic firearm.
COMPANY POLICY
Orders paid for with a Canadian credit card MUST be shipped to Canada.
Orders paid for with a USA based credit card can be shipped to Canada.
We accept orders from Canada with a purchased parts value up to $500.
Orders containing restricted parts requiring an export license from the U.S. Department of State are not accepted. We do not obtain export licenses through the State Department.
Orders for firearm parts from Puerto Rico and U.S. Virgin Islands may be subject to additional filing requirements and can take more than 48 hours to process.
Please note the dealer discount is not available for our Canadian customers.