Air pistols shooting over 500fps AND 4.2FPE are restricted firearms.
From the RCMP Airguns Fact Sheet...
1. Air guns that are firearms for purposes of both the Firearms Act and the Criminal Code.
These are air guns with both a high muzzle velocity (greater than 152.4 meters or 500 feet per second) and a high muzzle energy (greater than 5.7 joules or 4.2 foot-pounds). The “muzzle velocity” is the speed of a projectile at the instant it leaves the muzzle of a gun, normally expressed in metres per second or feet per second. The “muzzle energy” is the energy of a projectile at the instant it leaves the muzzle of a gun, expressed in joules or foot-pounds. Air guns need to meet both standards to be classified as firearms for purposes of the Firearms Act.
These high-powered air guns are subject to the same licence and registration requirements as a conventional firearm.
You are also required to store, transport, display and handle them safely in accordance with the regulations supporting the Firearms Act.
Usually, the manufacturer’s specifications are used to determine what muzzle velocity and muzzle energy an air gun was designed to have. This information may be available in the user’s manual or on the manufacturer’s web site. If the information is not available, individuals can call 1 800 731-4000 and ask to speak to a firearms technician to find out if the air gun is classified as a firearm for purposes of the Firearms Act.
High-powered air rifles are classified as non-restricted firearms. High-powered air pistols are classified as restricted if their barrel is longer than 105 mm or prohibited if their barrel length is 105 mm or less.