You will not have a problem importing a slide. A slide of a real firearm, let alone an airsoft gun, is not in itself a prohibited or restricted part and does NOT require any kind of permits to import. This is spelled out in the D-memorandum D19-13-2, which is one of dozens of regulation sources which the CBSA Officers reference regularly.
Even if confused with slide for a real pistol, it is not illegal to import a slide into Canada if properly declared.
The D-Memo D19-13-2 (http://www.cbsa-asfc.gc.ca/publicati...9-13-2-eng.pdf
) defines a firearm as:
"a barrelled weapon from which any shot, bullet, or other projectile can be discharged and that is capable of causing serious bodily injury or death to a person, and includes any frame or receiver of such a barrelled weapon and anything that can be adapted for use as a firearm."
(Page 5, right hand side).
This is where all the trouble comes from for importing receivers.
Just a word on the CBSA D-Memoranda. The D-Memos compile information from numerous Acts of Parliament into a single document that puts it all into the "import/export" context.[/B] The D-Memo referenced above, for example, presents info out of the Criminal Code, the Firearms Act, as well as the Export and Import Permits Act, while D-Memos pertaining to import/export of agricultural products may reference acts such as The Health of Plants and Animals Act.
Back to Airsoft parts and accessories, though! The Customs Tariff 9898.00.00 is also used to help with the determination of "prohibited devices". Feel free to read through it here on page 1757 of the PDF document to find out what's prohibited for import and what's not http://www.cbsa-asfc.gc.ca/trade-com...-01-99-eng.pdf