7Conversion not to affect classification
(1)Any weapon which—
(a)has at any time (whether before or after the passing of this Act) been a weapon of a kind described in section 5(1) of the principal Act as amended by or under section 1 above; and
(b)is not a self-loading or pump-action smooth-bore gun which has at any such time been such a weapon by reason only of having had a barrel less than 24 inches in length,
shall be treated as a prohibited weapon notwithstanding anything done for the purpose of converting it into a weapon of a different kind.
(2)Any weapon which—
(a)has at any time since the coming into force of section 2 above been a weapon to which section 1 of the principal Act applies; or
(b)would at any previous time have been such a weapon if those sections had then been in force,
shall, if it has, or at any time has had, a rifled barrel less than 24 inches in length, be treated as a weapon to which section 1 of the principal Act applies notwithstanding anything done for the purpose of converting it into a shot gun or an air weapon.
(3)For the purposes of subsection (2) above there shall be disregarded the shortening of a barrel by a registered firearms dealer for the sole purpose of replacing part of it so as to produce a barrel not less than 24 inches in length.