Specifications for imitation firearms
3.—(1) Blank-firing imitation firearms, other than those described in paragraph (2), must conform to the following specifications—
(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.
(2) The blank-firing imitation firearms described in this paragraph are—
(a)imitation revolvers; and
(b)imitation firearms where the blank cartridges are loaded vertically at 90 degrees to the dummy barrel and which fire, and vent the gases produced on discharge, in the same direction.
(3) Blank-firing imitation revolvers must conform to the following specifications—
(a)an imitation revolver must incorporate an inclusion cast into the dummy barrel and a separate inclusion cast into the cylinder which extends to fully obstruct all the dummy chambers;
(b)the inclusions 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;
(c)the inclusions should be permanent and incapable of being knocked out without destroying the chamber or barrel;
(d)the barrel inclusion must wholly block the dummy barrel and part of it must be incorporated into the rear of the dummy barrel;
(e)the barrel inclusion must be intended to prevent removal of the dummy barrel, unless the frame 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;
(f)the inclusions must be intended to prevent the creation of a hole through the dummy barrel or chamber along their axis; and
(g)the revolver must vent the gases produced on discharge at not less than 80 degrees from the axis of the dummy barrel.
This refers to the “Vickers hardness test” which is a method 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).