Proof and CIP

Every Eley shotgun cartridge carton has printed on it the gauge, chamber length, shot load and the proof level of guns from which the cartridges in that carton may be used safely. This information includes, for guns proved under the British 1954 Rules of Proof the service pressure in tons per sq. in. and for guns proved under the...

Every Eley shotgun cartridge carton has printed on it the gauge, chamber length, shot load and the proof level of guns from which the cartridges in that carton may be used safely. This information includes, for guns proved under the British 1954 Rules of Proof the service pressure in tons per sq. in. and for guns proved under the British 1925 Rules, the shot load. Additionally, for guns bearing European Proof Marks, the information given is the proof pressure in kg. per sq. cm. Any special features (such as Magnum loads) are particularly stressed so that users of Eley cartridges have adequate information to enable them to assess the suitability of
the cartridge for their gun. Steel cartridges marked as “High Performance” are only suitable for use in steel proved shotguns. A steel proved shotgun should have the words “Steel Shot” stamped on the barrel and or a
Fleur-de-Lys proof mark.

On June 5th, 1980, the United Kingdom joined the International Proof Commission (CIP). As a result of this, new Rules of Proof were introduced in 1984 and these were amended in 1986 and 1989.
There are now thirteen members of CIP whose proof marks are reciprocally recognised. The 1984 Rules of Proof introduced a transitional period of five years during which either Imperial or Metric markings could
be used at the discretion of the submitter on the weapon the following proof. With effect from October 1st, 1989 only Metric markings were allowed to be used; The actual proof marks used by Birmingham and
London have not changed only the marking on guns of the chamber length in millimeters and that of the pressure in Bars, (e.g. 850 Bar) whereas under the British system the Highest Mean
Service Pressure was shown. 

For 12 bore shotguns there are two levels of proof, Standard at 850 Bar minimum for chamber lengths up to 70mm and Superior or Magnum at 1200 Bar minimum for all chamber lengths above 70mm. The maximum average cartridge pressures for use in chamber lengths up to 70mm being 650 bar and for chamber lengths up to 89mm being 900 bar. Note these pressures relate to the CIP Radial Crusher system of pressure measurement; the later Transducer system uplifts these values by approx 14%.

All Eley cartridges conform to the dimensions and ballistics stipulated in the internationally recognised regulations issued by Commission Internationale Permanente (CIP). Cartridges are regularly tested for
compliance with these regulations and all packaging materials clearly show the CIP approval mark which we are permitted to use following an assessment of our testing facilities and evaluation of products by
The Birmingham Gun Barrel Proof House – one of the appointed assessment bodies for the United Kingdom.

Further information about the marks and other Proof matters can be found in the booklet “Notes on the proof of shotguns and other small arms”, 5th Edition,
November 1993, available from either:The Birmingham Gun Barrel Proof House, Banbury Street, Birmingham B5 SRH. http://www.gunproof.com/ email [email protected]
or

The Gunmakers’ Company, London. 48 Commercial Road, London E1 1LP. Tel: 0207 481 2695.