Specifications for imitation firearms
4. The specifications referred to in regulation 3(1) are that—
(a)an imitation firearm must incorporate an inclusion;
(b)the inclusion must be wholly made of a material which is at least as resistant to being cut, drilled, bored, ground (or any similar process) as sintered tungsten carbide in the range 1550-2000 HV 30(1);
(c)the inclusion must wholly block the barrel and should be permanent and incapable of being knocked out without destroying the chamber or barrel;
(d)part of the inclusion must be incorporated into the rear of the dummy barrel; and
(e)the inclusion must be intended to prevent—
(i)the creation of a hole through the dummy barrel along its axis; and
(ii)the removal of a dummy barrel, unless the frame and chamber area of the firearm is rendered useless as a result or its integrity so compromised that it cannot be used to form the basis of a firearm without significant repair or addition.
This refers to the “Vickers hardness test” which is a method used to measure the hardness of materials. The test can be used for all metals. The unit of hardness given by the test is known as the Vickers Pyramid Number (HV).