We’re talking about the British Mk 3 and Mk 4 helmet shells. There are two points. It turns out there’s some degree of uncertainty as to the actual production years of these helmets, especially as to when they ceased production. Also, there is a theory, propounded by the estimable Roger Lucy, that Knowledge can be obtained from examining the batch codes stamped inside most (but not all) of these helmet shells.

Popular understanding has it that the Mk3 (that’s the one with the bolt-in liner and the high-set chinstrap lugs) came into production in 1944, with the revised version, the Mk 4 (lift-the-dot liner, lower set chinstrap lugs) in 1945 (contract awarded December ‘44).

It isn’t clear when production of the Mk3 ceased, though it would be reasonable to believe it would have been at the time Mk4 production was started. It is said - Cotton, MILITARIA MAGAZINE article 1995 - that 1-million+ Mk4 helmets were ordered in December 1944 - but Cotton himself later implied that few were actually produced soon after. It is thought - perhaps wrongly - that there were two bursts of production, one immediately at the end of WW2 and the other during the Korean crisis of the early 50s.

Given the present lack of the promised book by M Cotton which will make everything clear, the best we can do is try, by looking at the actual shells, to establish a fair idea of the period(s) of production. It is generally believed, for example, that there are *no* shells dated after 1953. Is that true?
So the task is simple but difficult. Just examine the shells of your Mk3 and Mk4 (which includes the notional Mk5 which is after all only an old Mk 4 shell with a different liner and a fresh coat of paint).

The difficult part is that the manufacturers stampings can be hard to locate, hard to read, and maybe not even there in the first place. And may have been totally obscured by many coats of paint. Look under the front brim, or around the chinstrap lugs. Stampings can be aligned either horizontally or vertically. There’s no pattern or sense to it.

What you will be looking for is a grouping of letters and digits that will probably (not always) comprise something like this -

RO&CO CA 1952 4

but *not * in a line like that. That information is the manufacturer (RO&CO, or BMB), a batch code, the date, and the mark of helmet (this could be 3 or 4, or III or IV).

These stamps are often very lightly struck and will be difficult to read - use a bright light angled against the metal to bring out the lines. Even if you cannot make out all the characters just the maker and date will be good.

The more I (and Roger) have looked into this the more we realise the published information is inadequate and that the more we find out the less we know. This is useful research, please help.

This is what I have been able to read from part of my collection (some unreadable, some inaccessible at the moment) -

Mk3

RO&CO DO 1944 III

Mk4

RO&CO FS 1945 4
RO&CO FS 1945 4
RO&CO FF 1945 4

RO&CO DI 1952 4
RO&CO CA 1952 II (that’s really what is there!)
RO&CO MA AD 1953 4

BMB A3 (no date) 4
BMB C791 (date unreadable) 4
On the basis of this sample it does seem to reinforce the idea that there *was* indeed a substantial batch produced immediately after the Mk4 contract was awarded. And the Korean War crisis run seems to be reflected also. And is it really true that no shells were pressed after 1953?