The Three Legal Classes of Firearms in Canada:
Non-restricted firearms are ordinary hunting and sporting rifles, shotguns and airguns with an overall length of 660mm or greater. Many airguns fall into this class because they are capable of achieving a muzzle velocity of 500 feet per second. If it is a centrefire semi-automatic firearm, the barrel length must be at least 470mm to be non-restricted. These firearms must be stored, transported and displayed according to Federal regulations and you need a firearms licence to possess them. Provincial and municipal rules may further regulate these firearms (e.g., Ontario hunting regulations require that firearms being transported be encased at night). Certain firearms, although they meet the above criteria, have been classified as "restricted" or "prohibited" by order-in-council.
Restricted firearms include many handguns and other firearms which do not meet the above specifications. Some firearms are classified as "restricted" by Federal order-in-council. All variants of the AR-15 genre of rifle are restricted firearms. A transport permit is required to transport a restricted firearm from the location where the firearm is registered. Anyone with the appropriate firearms licence and a valid purpose can acquire this type of firearm. Hunting with restricted firearms is not allowed in Canada.
Prohibited firearms include all fully automatic firearms, converted automatics and a variety of other scary looking firearms which have been classified as "prohibited" by order-in-council. Most types of prohibited firearms are "grandfathered" to their current legal owners (i.e., owners are allowed to keep them), but cannot be transfered to non-grandfathered individuals. Firearms converted from full-automatic to semi-automatic, and many handguns (barrel lengths less than or equal to 105mm, .25 or .32 calibre) fall into the prohibited class. If you do not already own prohibited long guns, there is generally no legal means to acquire firearms of this type.