Belgian 75x277R Case Manufacturer

I have a fired Belgian 75x277R Case headstamped:

LOT 7-----------1938

The primer is a standard large 3-slot screw-in type and is marked: “[A.F.M.]” 310 (Lot number?), and “51” in one tool slot, and “34” in another (Inspector’s marks)?. Any info on the maker of this case and primer would be helpful. Also, what does “C.75.T.R.” stand for?


I think it’s a case for the belgian 75mm fieldgun.
C.75.T.R.= Canon de 75mm Tir Rapide
OM= case manufacturer, but unknown to me

AFM= french primer manufacturer: Atelier de fabrication de Munitions
34 will probably be the year (1934)


Does anyone have any idea on the manufacturer “O.M.”?



I can’t help with the identification of “O.M.”, but can explain the primer markings, other than “AFM”, which Krt has already done. “310” is the cartridge lot number, “51” is the primer lot number, and “34” is the primer model (Model 1934).


Thanks for the information.

What is the best source of information to identify headstamps on ammunition 20mm and above? There seems to be very little information around.


There is no single source of information on headstamps for 20mm and larger ammunition.  If fact, once you exceed 37mm caliber, most of the information is generic in nature (e.g. "Typical US 75mm case markings").  Basically, you need to accumulate a large library of official and commercial publications and articles, and a good idea of what they contain, in order to identify and understand case and primer markings.  Even with this, many will remain a mystery because that information was considered unimportant in official sources, or the document that covers it was a very limited printing that may not even be known.  I had considering publishing an article containing drawings of various headstamps 37mm and up, including the primer markings, for most countries that produced ammunition or had it made for them with distinguishing markings (primarily for the 1880-1945 period), with an explanation of these marking, but found the task was absolutely overwhelming considering the number of entries required, the availability of items to draw, and my limited ability to draw in the exact manner required in a reasonable period.  A project of this nature, to be thorough, would likely require several knowledgeable people with access to large libraries and collections, superb drawing abilities or including someone with those abilities, and several years of intensive, dedicated labor.  I might add that CAD drawings are no substitute for handmade drawings by a skilled individual, so technology provides no shortcuts for this type of endevour. 


Jim- You are correct that a comprehensive listing with ALL headstamps drawn to perfect detail would be wonderful. You are also correct that it would be a massive undertaking for an individual, or even a team.

Since the “perfect” solution is clearly unattainable, can we beg you to consider a “less than perfect” solution?

Given the dearth of information in this area, how about one or more of the following formats?:

a. A simple listing in table format with plain text for the markings and “[ordnance wheel]” or “[flaming bomb]” to represent symbols? Just a sentence or two of identification- caliber, country, time, special features.
b. Drawings done by CAD, accepting they may not be optimum representation of the precise marking.
c. Use of photos instead of drawings- even if it takes 3 or 4 photos to show the desired details. Color digital photos are EASY and many people just use scanners. (Mel Carpenter has promised to share the secret of how he gets such great images of the Gyrojet/MBA stuff he has send for Cartridge of the Month… so we can all see how easy it is.)

Instead of the goal of a massive comprehensive list, let’s get something in some easy format to share in increments of 10, 20 or 25 items at a time.

We can post it on the website for comment (Or ridicule? If someone thinks they can do better- they are welcome to take pen to paper to start drawing…). Or, Chris P. can use a page or two in the Journal as they become available.

Can we count on you for something on 10 items a week, or 25 a month, in any format you want to try that is easy? They don’t have to appear in any logical sequence. If done as digital documents and images, they can be sorted out later.

Let’s share some of the massive info you have accumulated from years of study!



I'll give this some serious thought, but cannot devote an unlimited amount of time to it at present because of prior committments.  I do have a number of good hand made drawings prepared already.  It's not necessary to draw all headstamps, only those that show a distinct style or important variation.  For example, almost all WWI German Army headstamps, whether 3.7cm or 42cm, follow a standard format, as do WWII Japanese Army and Navy headstamps 37mm and up.  In this type of situation, one example is sufficient to show the headstamp style for all cases with this headstamp format, regardless of caliber.

In the next few weeks, I’ll attempt to post some drawings, but not too many at one time because of the space they’ll take up. All are actual size, and range in caliber from 37mm through 101.6mm, so are not small.

I cannot do CAD drawings, and am not too skilled at photography. As for lists of markings, I’m not convinced that they would be of the same value for identification as a drawing or high quality photo.


I have some drawings I have done by hand and in MS paint, but I doubt they would be of sufficient quality to use in an actual guide. I think a guide with just markings for 20mm would be useful, as information is hard to get even on 20mm headstamps. There is also the smaller range of rounds between .50 BMG and 20mm which could make another guide, also rounds below .50 BMG such as 11.35mm Madsen, .50 Vickers and 12.7 Breda. This guide could be a simple text listing. Maker’s marks on large calibre cases from one country such as the UK could also be done in text format, I could put that together.

I am thinking a guide made in the following format:

/|: Royal Ordnance Factory, Radway Green, Cheshire, England
BM: British Manufacturing and Research Co., Grantham, Lincolnshire, England
B.M.A.R.C.: British Manufacturing and Research Co., Grantham, Lincolnshire, England
BMO: British Manufacturing and Research Co., Grantham, Lincolnshire, England
ECC: Edward Curran & Co., Bute Docks, Cardiff, Wales
K: Kynoch Factories, Imperial Chemical Industries Ltd., Witton, Birmingham, England
K2: Kynoch (I.C.I.), Standish, Lancashire, England (Part of War Emergency Expansion plan, operational 1942-1944)
R.C.C.: Raleigh Cycle Co., Ltd., Nottingham, England
RG: Royal Ordnance Factory, Radway Green, Cheshire, England
R.H.: Raleigh Cycle Co., Ltd., Nottingham, England
RL: Royal Laboratories, Woolwich, London, England
RLB: Royal Ordnance Factory, Birtley, Newcastle-Upon-Tyne, England
ST: Royal Ordnance Factory, Steeton, Yorkshire, England
VAEL: Vickers-Armstrong Engineering Ltd., Barrow-in-Furness, Cumbria, England
V.S.M: Vickers, Son and Maxim Ltd., Barrow-in-Furness, Cumbria, England

There are many, many more. This is only a short list. The guide could also include calibres these headstamps known on.