Which of the following is NOT a class characteristic of a firearm?

• A. Caliber of weapon and ammunition
• B. Shape of the firing chamber
• C. Location of the firing pin
• D. Weight of the shooter

Answer: (D)

In forensic firearms analysis, the concept being tested is class characteristics—the features of a gun or ammunition that define a group and help identify the general model or type. These are fixed design or manufacturing traits that are shared by firearms of the same make or model.

Caliber of weapon and ammunition is a classic example of a class characteristic because it reflects the size and standard cartridge that the firearm is designed to use. The shape of the firing chamber is another design feature that helps classify the firearm. The location of the firing pin is also tied to the gun’s mechanism and design, making it a class characteristic.

Weight of the shooter, on the other hand, is not a property of the firearm itself. It does not reflect the gun’s construction or the ammunition it uses, and it cannot be used to categorize or identify a firearm. It may influence behavior or recoil, but it isn’t a characteristic used to group firearms.

Therefore, the item that is NOT a class characteristic of a firearm is the weight of the shooter.