http://www.legislation.gov.uk/uksi/1980/640/signature/made
The Gun Barrel Proof Act 1978 (Commencement No. 2) Order 1980
Westlaw
King's Printer of Acts of Parliament
2011-04-05
ARMS AND AMMUNITION
This Order brings into operation on 5th June 1980 the provisions of the Gun Barrel Proof Act 1978 not already in operation, that is, sections 1, 8(1) (so far as not already in force) and 8(3), Schedules 1 and 2 and certain minor amendments in Schedule 3, all of which relate to the Convention for the Reciprocal Recognition of Proof Marks of Small Arms (Cmnd. 5942).
Sally OppenheimMinister of StateDepartment of Trade