It is to be found under the barrel just foreward of the receiver, and requires removal of the fore-end woodwork to view. It is possibly the diminutive size of this mark, and its usually hidden location, which has led to it being described as 'secret'.
In this instance, the code letter is 'M' for 1932-33, indicating that the rifle was manufacture, or at least proved, between July 1932 and June 1933. Post-War rifles such as the BSA Model 12/15 will not carry this mark.
However, we have been made aware, by a contributor, of two contemporary rifles, a BSA Mk.
However, if an estimate of the rifle's age from other sources closely matches the date marks, then you probably have pinned down when it was made within a year or so. The ISBN numbers for these reference books are in the bibliography. When inspecting your rifle and comparing marks with reference sources, be careful not to confuse date marks, or "private view marks", with inspectors marks, which usually carry the factory identification, e.g., "E" for Enfield, under the sovereign's crown, below which is the inspector's identification number; usually two figures such as "39". rifles the Proof mark is only on the barrel (and on the action falling-block), and the third mark on the barrel is the 'NP' mark for Nitro-Proof, also below the crown.
Many, but not all, of our pages carry date information on the various rifles illustrated or discussed, where it has been possible to be sure of data.
There are a number of methods by which a rifle can be dated, or at least bracketed between certain years of manufacture.
Quite apart from such dating information as we have been able to provide on many of the individual rifle types included on this website, there are other ways in which you may be able to confirm the date of manufacture, or at least the date of proof, of your rifle.
Do remember, though, that date information coded with proof and Proof-House inspection, viewing or identification marks, does not necessarily coincide with the date of manufacture. have, for many years, been legally required to carry proof marks from one or other of the Proof Houses.