Category A

Rimfire rifles, single or double barrel shotguns, paintball guns, air rifles, and powerheads.
(1 ) Each of the following is a category A weapon if it has not been rendered permanently inoperable—
(a) a miniature cannon under 120cm in barrel length that is a black powder and muzzle loading cannon, depicting a scale model of an historical artillery piece or naval gun;
(b) an air rifle;
(c) a rim-fire rifle (other than a self-loading rim-fire rifle);
(d) a shotgun other than a lever action shotgun, pump action shotgun or self-loading shotgun;
(e) a powerhead;
(f) a break action shotgun and rim-fire rifle combination;
(g) an air gun;
(h) a weapon mentioned in any of paragraphs (a) to (g) that is a blank-fire firearm. (2) A conversion unit is also a category A weapon. (3) In this section— air gun means a firearm designed to discharge a projectile (including, for example, an arrow) by compressed air, or other compressed gas, not generated by an explosive. conversion unit means a unit or device or barrel that is capable of being used for converting a category A weapon that is a firearm from one calibre to another calibre.

Category B

Centre-fire rifles (other than semi-automatic)
Shotgun/rifle combinations
Lever action shotguns with a magazine capacity of no more than five rounds. 

(1) Each of the following is a category B weapon if it has not been rendered permanently inoperable—
(a) a muzzle-loading firearm;
(b) a single shot centre-fire rifle;
(c) a double barrel centre-fire rifle;
(d) a repeating centre-fire rifle;
(e) a break action shotgun and centre-fire rifle combination;
(f) a lever action shotgun with a magazine capacity of not greater than 5 rounds;
(g) a weapon mentioned in any of paragraphs (a) to (f) that is a blank-fire firearm. (2) A conversion unit is also a category B weapon. (3) In this section— conversion unit means a unit or device or barrel that is capable of being used for converting a category B weapon that is a firearm from one calibre to another calibre.