Here is the official statement from the CBSA:
1. The purpose of this notice is to advise of changes affecting the classification of 6mm calibre airsoft guns.
2. Section 2 of the Criminal Code 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, as well as anything that can be adapted for use as a firearm”.
3. As outlined in Memorandum D19-13-2, Importing and Exporting Firearms, Weapons and Devices, it was previously established that an airsoft gun, firing a .22g 6mm plastic pellet, must have a muzzle velocity in excess of 124 m/s (407 fps), in order to be considered a firearm.
4. Based on the latest research, it is now established that the muzzle velocity at which a .20g 6mm plastic airsoft projectile is capable of causing serious bodily injury is 111.6 m/s (366 fps).
5. Airsoft guns, firing a .20g 6mm plastic pellet, with a muzzle velocity above 111.6 m/s (366 fps), will be classified as firearms. Please refer to D19-13-2 for the import requirements of low muzzle velocity firearms, including low muzzle velocity “uncontrolled” firearms.
6. If an airsoft gun, firing a .20g 6mm plastic pellet, shoots below 111.6 m/s (366 fps), and resembles with near precision an existing make and model of a firearm, other than an antique firearm, it will be classified as replica firearm. Replica firearms are prohibited devices and must meet import requirements as listed in D19-13-2.
7. Inquiries and comments about this notice should be directed to: Other Government Department Programs Unit Programs Branch Canada Border Services Agency E-mail: email@example.com