Many papers and books have been written on this subject, but probably the most authoritative is 'The Standard Directory of Proof Marks' by Wirnsberger, distributed by Blacksmith Co., Southport, Connecticut 06490. This is, however, a very complex subject and requires much research and experience in the interpretation of the marks before accurate information can be obtained. In these cases, the proof mark could prove to be the only method of accurately dating a weapon. To complicate matters further, modern reproductions of some of these old weapons have been produced, which are often virtually indistinguishable from the original. This, however, no longer holds true as many weapons, for example, the Colt Single Action Army Model of 1873, are well over this age and can fire modern centre fire ammunition. At one time, the situation was simple, with an antique being considered to be anything over 100 years old. Many countries have specific exemption from their firearms legislation for weapons which are ' antique'. Proof marks can be a very valuable aid to the forensic firearms investigator as they can give information as to the age, history and country of origin of a weapon. Reproof is an additional test which may be applied after a weapon has been repaired or altered in some way.

Generally, this calls for between 30 and 50% increase in pressure over the standard round of ammunition. Definitive proof applies to all weapons and shows that the weapon has been tested with an overcharge of propellant and missile.This type of proof is designed to prevent the manufacturer from continuing work on barrel blanks which may have hidden defects. Provisional proof is only for shotgun barrels in the early stages of manufacture.There are basically three types of proof: provisional proof, definitive proof and reproof. Weapons bearing military proof marks have thus to be commercially proofed before they can be legally sold in those countries. These, once again, are not accepted by theД®uropean commercial proof houses. There are also a number of countries which have a separate military proofing system for service weapons. For various reasons, these have not been acceptable to the European commercial proof houses, and the weapons have to be fully proofed before they are legally saleable in those countries. At present, these include Austria, Belgium, Chile, Czechoslovakia, Finland, France, Germany, Hungary, Italy, Republic of Ireland, Spain and the United Kingdom.ДЄ number of other countries have their own forms of proof, either in-house or centrally run. A number of other countries have also established their own proof houses and by agreement at consular level, reciprocal arrangements have been made for their proof marks to be mutually accepted. In England, the London and Birmingham proof houses were established (in 16, respectively) by Royal Charter to protect the public from the sale of unsafe weapons. Proof marks are stamps applied to various parts of a weapon during and after manufacture to show that the weapon is safe for use with the ammunition for which it was designed.

Browning serial numbers proof house