The bullets go in the clip...right?

Pulled bullet and an intact cartridge

If you want to utter terms that make a firearms examiner shiver (a phenomenon similar to saying splatter to a bloodstain pattern analyst) on the stand, continuously use the term bullet for cartridges and clip for ammunition magazine. We'll focus on cartridges for today.

Bullet is used colloquially to name an unfired piece of ammunition for a firearm. Cartridge is the term a firearms examiner would prefer you use. Using bullet sets up the situation where the examiner has to correct the term before being able to answer the question, or potentially seem nonchalant about technical terms when the transcript is read later. You also run the risk of not impressing the juror that happens to know a lot about firearms and ammunition, such as if you have a juror that loads their own ammunition.

Looking at the photograph, a bullet is the part of the cartridge that travels down the barrel. In the image, the pulled bullet is on the left, and it is placed above the cartridge case (note: not casing, just case). So there is a correct time to refence just the bullet, which is where terminology becomes important. Frequently when testifying about firearms analysis, the expert will need to be able to refer to unfired cartridges, fired bullets, and fired cartridge cases. Using the terms interchangeably will make the testimony hard for jurors unfamiliar with firearms to follow, and loose credibility for the questioner and perhaps the expert with those familiar with appropriate terms. In the photograph, the cartridge (which would get loaded into an ammunition magazine) is on the right.

The propellant sits below the bullet in the cartridge

Each propellant has a different design based on what the ammunition company is trying to achieve

Beneath the bullet and inside the case is the propellant. This is the substance that rapidly burns to provide the energy to push the bullet down the barrel. This will also provide the energy in a semi-automatic firearm to cycle the firearm, unlocking the barrel and breech/bolt, then ejecting the fired cartridge case. Propellants will have different shapes, perforations, and coatings that will change how it burns. In this example, this Chinese designed cartridge is using short segments of a tubular grain type, a choice I do not see often for 9mm Luger caliber ammunition (this was from the pulled bullet case above).

Not pictured is the final component of a cartridge, the primer. This is a multi-component part, but is seen from the head of the cartridge case (side opposite of the bullet) as a disk. The primer gets crushed by the firing pin, and a shock sensitive compound inside explodes, shooting molten material into the propellant, which ignites the propellant and starts the combustion process.

This covers the four main components of a cartridge. Reading this short primer, you now know the appropriate terms to question and expert or understand their report and testimony, and to stop using the term bullet when you do not mean bullet.

If you want to know anything else about ammunition or want me to explore a different topic, leave a comment on this post.