The simplest method of identifying a cartridge caliber is to look at the head stamp.

For most firearm enthusiasts, it is important to have some basic knowledge on cartridge identification. In most cases, the head stamp will quickly tell you precisely what type of ammunition it is. On most cartridges, the head stamp is stamped at the head, or flat part of the cartridge.

However, the information that one derives from the head stamp can vary depending on who will be using the cartridge and who is the manufacturer. Some of the older cartridges will have partitions or segmental lines that divide the head into 2 or 4 equal areas. These segmented cartridges are no longer manufactured.

What has transpired over the past 4 decades has been a rapid expansion in ammunition manufacturing. Recent global wars have resulted in upgraded manufacturing processes, new manufacturers and thus, during this rush, there has been little attempt at standardization. It appears that every manufacturer has their own headstamp style. While some manufacturers use the three element space, equidistant from each other, other manufacturers have adopted a four element protocol.

The location of the elements is based on a clock face orientation and is now a universal feature in modern cartridges. The top starts at 12-o’clock, the right is 3-o’clock, the bottom is 6-o’clock and the left is 9 o’clock.

Military Headstamps:

The standard US military ammunition headstamp before the Second World War had two elements: the factory code at 12-o’clock and the date of manufacture at 6-o’clock. Today, most US military ammunition contains anywhere from 2-5 elements.

The maker is almost always identified on all headstamps. Military ammunition usually includes the date and the civilian ammunition will often have the caliber information. In general, the head stamp will provide information on several key elements.

1. Cartridges meant for civilian use or for enthusiasts, will typically have two elements: namely, a) identification of the specific chambering and b) the identity of the manufacturer.

2. Cartridges meant for military personnel may have anywhere from one to five elements which include a) type of cartridges b) date of manufacture c) place of manufacture and d) any other identifying markings.

3. A headstamp will help identify who made the cartridge, the year it was made, a model of the mark, type of powder and sometimes even denote if it is for special use. The purpose of the cartridges may be denoted by an extra marking; one will need to look at the chart to determine the purpose of each ammunition.

4. To identify the manufacturer, one needs to look for the two-letter code that is frequently separated by a broad arrow.

5. To identify when the cartridge was produced, one will need to look for the 2 or 4 digit. For example, it may say 1972 or 72.

6. To identify the model one looks for Roman numerals that are usually numbered from 1 to 8.

7. To identify the powder it may state “C” which indicates that cordite was utilized or there may be a Z indicating that it was nitrocellulose powder.

8. In some cartridges, the factory code which was always at 6-o’clock in the past has now been moved to other locations.

Be warned, there are some markings that are intentionally deceiving to avoid government bans. For example, some Chinese ammunition intended to arm other countries will only reveal a false manufacturer and no other detail.

Civilian or Commercial Headstamps:

Modern commercial cases are somewhat standardized for safety. Cartridge designation is printed on both the cartridge box and the headstamp and should be matched to the identification of caliber with the gun to be used.

Commercially available cartridges have the manufacturer and caliber on the headstamp in the double element positions. Some cartridges have more than one designation. An example includes the common caliber 9mm which can also be 9 MM Para, 9 MM Luger or 9×19 MM. Some ammunition has a “+P” or “+P+” designation, indicating it is loaded to higher-than-standard pressure levels for better ballistic performance. This higher-pressure ammunition must be used only in those guns certified for it, as shown on the barrel, slide or frame. Always user proper ammunition in your gun.

In addition to the 400 commercial head stamps, globally there are at least 800 military headstamps. The field of head stamps is complex and anyone who wants to go deep into it will need a book to recognize them or visit one of the many online forums where cartridges are often identified.

Finally, it is important to known that it takes years of experience to be good at identifying head stamps. There are now large library collections of all ammunitions and sometimes despite your best efforts, you may not be able to identify them.

When sorting and reloading ammunition, be sure to check headstamps for consistency and identify any cases that are unusual or you do not immediately recognize. Capital Cartridge specializes in sorted brass cases with mixed headstamps. These orders are filled with brass cases of the same caliber, but may be from multiple manufacturers for your bulk brass orders.