303 Mk IV - headstamp code 6 (C or G) IV


I have had in my collection for a long time a mark 4 hollow nose 303 It’s headstamp is at 12 o’clock a faint but very visible 6 then at about 5 o’clock
there is a C and at 7 o’clock 1V
The headstamp [not identified ]is shown on page 42 of THE MILITARY 303 CARTRIDGE
It’s History and Variations by Lynn H. Harris.
It came to me in the early 80’s when I purchased a collection from a New Zealand collector, there were also other mark 4’s of CAC N.Z. origin.
So I have assumed it also to be a product of CAC.
But over the years noting references to the cartridge factories of Great Briton
being expressed in numbers, e.g 2 =ROF WOOLWICH 3 Govt. fact. Blackpool, I have always suspected it did not really belong in the CAC section, Have exhausted all possible references, Does anyone know??


The round you have is not a CAC product but made at Royal Laboratory Woolwich.

In addition to rolling its own brass strip and producing cases, Woolwich also bought in cases made by commercial suppliers and loaded them at RL. This was partly to supplement Woolwich production but also to act as educational contracts to ensure that the commercial contractors maintained the ability to produce .303 in time of war. To identify these cases Woolwich used a numbered code for the manufacturer instead of the normal RL code. The case suppliers 1,2,3,4,5,6 and 8 exist, but 7 has never been seen. No record has been found though of which code belongs to which manufacturer.

Occasionally Woolwich bought in the brass from local foundries and made that into cases. When that happened a number was added to the normal RL headstamp. The numbers 1 to 5 are known, plus the Indian “broad arrow over I” which indicates brass from the Indian Government Rolling Mills at Cossipor.

Thus, an RL headstamp means cases made at RL with their own brass, RL plus a number means RL made cases using outside contractors brass and just a number code means RL loaded rounds with outside contractors cases.

This arrangement seems to have existed from around 1890 with the introduction of the .303 Powder Mark II until the commencement of Cordite Mark V production in 1899/1900 production year.

The second part of your question refers to the Government Cartridge Factories set up in 1916/17 and which only made .303 from late 1917 to 1918, previously having made 7.62 x 54mm for the Russian Government. There were four of these, although it is very unlikely that GCF4 ever made .303":

GCF1 at Blackheath, Staffs, managed by Birmingham Metals & Munitions
GCF2 at Woolwich, managed by RL
GCF3 at Blackpole Worcs, NOT Blackpool, managed by Kings Norton
GCF4 at Edmonton, London, managed by Eley Bros.

GCF2 used the RL headstamp and the other three used G.(date).F.1, 3 or 4. The G in the headstamp can sometimes appears as a C and it is unclear whether this was a second version of the headstamp.

I think that about covers it,


Thank you Tony, The only reference to the Number six on a 303 case that I could find was [unidentified ] 1973.


Hi all - I am positive that .303 cases headstamped ‘6’ were made by the King’s Norton Metal Company (& loaded by the Royal Laboratory) Evidence is too long-winded & complex to relate quickly. All will be explained in my booklet on the KNMCo - when it’s done - it’s only taken 30 years so far!!! Regards JohnP-C.
PS it’s a nice headstamp. I also have 6 C I & 6 C II (also have alternative style with ‘6’ reversed)


Similarly, I think from the available evidence that manufacturer 1 was Kynoch. Again the evidence is somewhat circumstantial but until an original listing is found it is all we have.