Firearms licensing: proof
Procedure
Submission to proof
Any individual may submit arms for proof or reproof direct to either of the two Proof Houses, but it is more usual, and generally more satisfactory for all concerned, that arms be submitted through a gun dealer. Primarily this is because the majority of old guns require attention prior to proof.
Proof Regulations require that shotgun barrels shall be "struck up" and smooth and that insides shall be clean. Pitting should be removed so far as is practicable, bulges knocked down and dents raised. Actions should be in good safe working order and tight on the face to resist the increased strain of proof pressure. Since stocks, and particularly those with unusual "bend" or "cast", are not designed to withstand the heavy recoil of proof, it is customary for the wood to be removed. Indeed, the Proof Houses do not accept responsibility for damage to stocks resulting from proof.
It will be apparent that to fulfil these requirements, the preparation necessary will best be undertaken by a gunmaker who is accustomed to submitting to proof.
Rejection
In the event of a proof rejection, or failure to withstand the proof test, guns may be repaired and resubmitted. On final rejection, that is when the submitter accepts that further attempts at repair are unlikely to succeed, the existing proof marks upon the barrels and/or action will be defaced or barred out.
It is unlawful for a weapon to be sold with defaced proof marks, except where later reproof marks have been impressed. It is recommended that such guns be deactivated, so as to ensure that it can never be used by some person unaware of its unproved condition.
Memorandum on black powder guns
Up to 1887 there was provision only for the proof of guns for black powder; but by that time the use of smokeless or nitro powders was commonplace. In that year a proof to cover their use, supplementary to definitive proof, was introduced. The service load of the powder intended for use, i.e. E.C. or Schultze, was then impressed on the barrel at proof. Under the 1896 Rules, proof to cover the use of nitro powders was still supplementary to the ordinary proof for black powder, but the words "Nitro Proof" were introduced as a proof mark.
The NP marks were introduced in 1904 but the nitro proof test remained optional until 1925, when new Rules of Proof made it obligatory. By that time most gunmakers had been voluntarily submitting their guns to nitro proof for many years.
Except on guns proved since February 1955 the NP marks were always used in conjunction with the words "Nitro Proof". The black powder proof marks remain valid, and a gun bearing them may still legally be used with black powder cartridges, provided it has not undergone any alteration taking it out of the category and state in which it was originally proved. Such alterations include conversion to ejector, rebrazing the lumps, increasing the depth of the chambers to take a longer cartridge or the enlargement of barrels beyond certain defined limits.