from the article:
Ottawa - Canada Post today announced amendments to the Non-Mailable Matter Regulations prohibiting the mailing of inert of replica munitions into
of Canada, or within
Canada. The new regulations became law effective October 4, 2006.
so out of, into and within. Not sure if it applies to g36 mags or not, as the definition below clearly states inert munitions. Being inert means it was munitions once right? those fake bullets in a g36 mag are clearly not inert, nor will ever be munitions.
For a better definition of the amendment: http://canadagazette.gc.ca/partII/20.../sor220-e.html