Cartridge case terminology and identification

Identification of cartridge cases is important for any collector of WW2 ordnance. A basic knowledge of terminology will help a collector identify the calibre, origins and use of a cartridge case.

First off, general terminology.

case terminology

As you can see from the above diagram, there are a number of terms that collectors use when referring to cartridge cases. The most important of these are the neck, shoulder, rim and head. All of these can give vital clues to identifying a cartridge case. The neck can give an approximate calibre, (although the diameter inside the mouth is more accurate), and the slope of the shoulder can differentiate between similar cartridge cases (e.g. 20mm Oerlikon has a much longer more graduated shoulder than 20mm Hispano-Suiza).


As this second diagram shows, the bullet is the projectile that leaves the weapon at high speed when the cartridge is fired. A cartridge case should never be called a bullet! It is simply NOT correct! The bullet itself has a core and a jacket, along with a groove called a cannelure. This can also help ID certain bullets.

Apart from the headstamp itself, (the marking on the base of a cartridge case), the rim is perhaps the most important. There are various types of rim.


This terminology looks, at first glance, to be a little complicated. However, it really isn’t! A rimmed cartridge is called that because the very bottom portion of the head, the ‘rim’, is wider than the main body of the cartridge. With a rimless cartridge case, the rim is exactly the same diameter as the cartridge case, which starts above the extraction groove. Semi-rimmed cartridge cases have an extraction groove and a rim very slightly larger than the diameter of the cartridge case. Belted cartridge cases have a thicker ‘belt’ positioned just above the extraction groove, and rebated cases have a rim that is smaller in diameter than the cartridge case.

As for the headstamps themselves, (the markings on the head of the cartridge case), these can give all sorts of information about calibre, manufacturer, year of manufacture, cartridge fill, cartridge type, (e.g. Armour Piercing (AP), Incendiary (I), Armour Piercing Incendiary (API), Tracer (T)), ‘mark’ of cartridge and even the type of alloy used to make the cartridge case.

You may find it easier to watch a video on this subject instead, so here is one I made a few months back. If not, keep scrolling down…..


To start with, here are the main allied small arms cartridges lined up so you can see the difference in overall shape and size. Take particular note of the difference between a standard 30calibre American cartridge and the British 303. Also note the difference between the standard 30calibre and the M1 Carbine cartridge (this is not live by the way! I remade it from a spent cartridge case and bullet found separately).

allied cartridges

Ok, on to identifying Allied small arms headstamps.

We’ll start with 20mm Hispano-Suiza cannon cartridges. A view of 3 cartridges found on various WW2 airbases.

20mm upright

Ok. Let’s look at the headstamps. You can see they all follow the same pattern. A letter ‘code’ which represents the manufacturer, a date stamp and a calibre. The right hand case therefore is made by RG (Royal Ordnance Factory, Radway Green, UK), in 1942. The middle case was made by I.C.I. , otherwise known as Kynoch in Standish, UK which is represented by the K2, in 1944.

20mm headstamps

Also, you may have noticed the chunks cut into the rim of the cartridge. This is not modern damage but damage caused by the breech block forcing the cartridge into the breech and then extracting it again as the gun cycles.

With American cartridges, the headstamps are usually very short, sharp and sweet ! Take for example these 50 calibre cartridges, again found on various airbases around the UK.

50cal upright50cal headstamps

The headstamps on these are not as detailed as some. Usually you get the manufacturer ‘code’ and the last two digits of the year, EXCEPT in the case of 1944 which is always represented by a single ‘4’. So on these cartridges you have RA 43, TW 43, LC 43, SL 4 and DM 4. RA is Remington Arms Company, TW is Twin Cities ordnance plant, LC is Lake City Ammunition Plant, SL is St Louis Ordnance Plant and DM is Des Moines Ordnance Plant.

These headstamps are repeated in standard 30 calibre and Carbine rounds. Take for example these 30 calibre cartridges, found on Slapton Sands.The headstamps all follow the same principals as the 50 cal cartridges.

30cal upright30cal headstamps

British cartridges tended to be a little more verbose. Take for example these cartridges, all found on an old D-Day practice beach.

303 upright303 headstamps

The headstamps, as you can see, contain a little more information. We still have the manufacturer ‘code’ and the year of manufacture (as either 2 or 4 digit), but we also regularly see ‘VII’ which denotes it is a standard Mark VII cartridge, and in some instances ‘303’ which obviously denotes the calibre. Different Roman numerals denote different ‘marks’ of cartridge. You may also see the marks ‘Z’ or IZ’ which denote the type of cordite/powder used. 303 cartridge cases can also have lettering to show the type of cartridge, for example a B would indicate incendiary.

It is interesting to note that the last three cartridges all have the same ‘odd’ shaped firing pin mark. This elongated mark is made by the firing pin of a Bren gun. A Lee-Enfield makes the ‘dot’ mark in the left hand two cartridges. So not only does the headstamp tell us something, even the firing pin mark can !

Now let’s look at 9mm and .45 calibre cartridges, again found on a D-Day practice beach.

9mm & 45 upright9mm & 45 headstamp

Now you can see a pattern emerging ! Hopefully you can now determine what the headstamps mean when you look at them. You have the manufacturer code, the year stamp and the calibre………….It’s easy once you know what you’re looking at !

The Germans used a little more complicated system than the Americans and British. Take for example these 7.92 calibre cartridges, all are ‘safe’ and were bought off a guy in an antiques place for 20p each ! He didn’t know what they were but I did because of a basic knowledge of headstamps. The cartridge cases have been married back with a bullet to be made whole, but all are empty and have used percussion caps.

german uprightgerman headstamps

Ok…..all German 7.92 calibre cartridges carry four stamps. As you look at the picture, at 12 o’clock is the manufacturers code. At 3 o’clock is a code with a combination of a roman numeral (I to XXII) for the steel mill supplying the basic case-metal, a lower-case letter for the plating agency and an arabic numeral (1, 2, 3, 4, 6, 8, 9, 10, 11, 12, 15 or 17) for the steel-analysis, which all identifies a copper-plated steel case. In some cases you may see a code such as St or St+ or S*. St stands for steel casing either lacquered or phosphated. St+ stands for improved steel casing lacquered or phosphated. * or S* indicates a brass case. At 6 o’clock is a batch number and at 9 o’clock is the year of manufacture represented by the last 2 digits of the year. Of interest is the fact that the Germans changed their manufacturer code system. Between 1937 and 1941 they used the P codes (Patronenfabrik Nummer). Between 1940 and 1945 (there was some overlap between the change of coding) they switched to a letter code and ditched the ‘P’ number. This means all ‘P’ coded cartridges are made prior to 1941, and all letter code cartridges are made from 1940.

So, for example, the far left cartridge was made by cg (Finower Industrie GmbH, Finow/Mark, Brandenburg), the case was made of St+ (steel case, plated), a batch number of ‘6’ (yes….i got it wrong on the picture !!! It’s a 6 not a 9 ), and a year of 1942.

The far right hand case is made by P490 ( Hugo Schneider A.G., Werk Altenburg), the steel mill code IX (August-Thyssen-Hutte A.G., Duisburg-Hamborn), the plating firm code w, (Hugo Schneider A.G. Messingwerke, Taucha-Leipzig), and the steel composition 1. The batch number is 7 and it was made in 1939.
I hope this of use to some of you. I know many will already know it but it’s good to pass on this sort of information !

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