Originally Posted by Styrak
Except an airsoft gun is not a prohibited item, unless Canada Post took you to a court and the court proved it so. So no, they don't care.
Actually airsoft isn't clearly defined. If it's being considered a Replica, then it IS categorized as a Prohibited Firearm.
In most cases they won't notice/care; but if your package causes a panic for some reason and forces the evacuation of a sorting facility, then I think they'll care a whole lot more.