Which of the following is one of the three ballistic categories of projectiles?

• A. Internal
• B. Surface
• C. Atmospheric
• D. Transitional

Answer: (A)

The correct choice is internal because it refers to the factors affecting a projectile while it is still inside the firearm, such as the chamber pressure, barrel length, and bullet design. Understanding internal ballistics is crucial for snipers as it influences accuracy, projectile velocity, and the overall performance of the ammunition.

The other options deal with different aspects of ballistics that can be important in certain contexts, but they do not represent one of the primary categories. Surface ballistics is not recognized as a formal category within ballistics. Atmospheric factors pertain to how external conditions like wind, humidity, and air pressure affect the bullet after it exits the firearm, which fall under external ballistics. Transitional factors may be related to the phase of the projectile's flight from the firearm to the atmosphere, but are not categorized independently in the same way as internal, external, and terminal ballistics. Thus, internal ballistics stands out as one of the foundational categories crucial for understanding how projectiles behave prior to exiting the firearm.