Another 2 Pounder headstamp

Shown below is a hand drawing of the headstamp of a 2 Pounder case made in 1929 by Royal Laboratories.

The case has the “N” indicating it was used by the Navy. Was there anything different about the case/charge that meant it could be used in both 2 Pounder Mk I and Mk II guns? What is a “9.5IN.D.C.T.”? I take it some sort of naval gun that the 2 Pounder was used for subcalibre training with. What does the extra “I” underneath the “II” marking on the top of the headstamp indicate?

I have never seen anything like the “fish” marking on the top half of the primer before. Is this a company logo or does it signify somethig about the primer? I am 99.9% certain it is not supposed to be a fish, but that’s what I thought it looked like.

Are the other markings on the case head such as “[GM]” underneath “RL”, the square box with a T and and I with a line through it, and the kite shape with a dot in above the D of D.C.T. acceptance stamps?

Sorry cannot help. As you know, big calibre stuff is not my forte, but I am sure that the DCT refers to a sub-calibre device.

Textbook of Ammuntion 1936 might help with the markings but I do not have a copy.


The “I” marking below the “II” indicates that this is a Mark I case. This Mark was used for the Mk.I and Mk.II Guns, as shown. The “9.5 IN. D.C.T.” indicates that this case was also for the 9.5" Depth Charge Thrower. When used for that application, it was loaded with a special propellant charge and the mouth closed with a wad and/or cup. The other markings on the case appear to be acceptance and inspection stamps, but I’ve no idea of what the “fish” symbol on the primer means. It’s likely to be a manufacturer’s logo.


Thanks Jim, was the 9.5" Depth Charge Thrower obsolete by the time of WW2? None of the WW2 dated 2Pr cases I have seen have this marking.

The 9.5" Depth Charge Thrower was still in service during WWII. I don’t know why the 9.5" marking was dropped, but assume that the Royal Navy decided that marking the 2Pdr cases for all possible applications was unnecessary. An excellent source of detailed information on what weapons were in service with all navies during WWII is “Naval Weapons Of World War Two”, by John Campbell. It was published in 1985 by Conway Maritime Press Ltd., 24 Bride Lane, Fleet Street, London, EC4Y 8DR, and also in the US by the Naval Institute Press, Annapolis, MD 21402. The ISBN is 0-87021-459-4. Most likely it’s out of print, but I’m certain a dealer in used military history books could locate a copy.