How to measure category H barrel lengths

Methods for measuring the barrel length of a category H weapon (handgun) are as follows:

• For a revolver – from the muzzle to the breech end immediately in front of the cylinder

For any other category H weapon:

• if the weapon has a breech bolt, from the muzzle to the breech face with the breech bolt in the closed position
• if the weapon has a top slide, from the muzzle to the breech face with the top slide forward; or
• if the weapon does not have a breech bolt or top slide, from the muzzle to the breech face with the break action closed.