Conventional air guns, air rifles and air pistols do not require to be held on a firearm certificate, unless they are of a type declared specially dangerous by the Firearms, (Dangerous Air Weapons) Rules 1969.
It is possible to measure the velocity of pellets discharged, to a satisfactory degree of accuracy, by use of an electronic chronograph. These measurements allow the calculation of the kinetic energy of the pellet, at the muzzle.
Such air weapons, exceeding these prescribed limits, can only be lawfully held
on a firearm certificate and are subject to all the rules and regulations pertaining to all Section 1 firearms.