What does "muzzle velocity" refer to?

Muzzle velocity specifically refers to the speed of a projectile as it exits the muzzle of a firearm. This measurement is crucial in ballistics because it directly affects the trajectory of the bullet, its range, and its impact power upon reaching the target. Understanding muzzle velocity is fundamental for calculating ballistic performance and estimating how a projectile will behave in different conditions.

The other options involve concepts related to the behavior of projectiles and sound, but they do not accurately define muzzle velocity. For example, the speed of sound in the barrel pertains to acoustic properties rather than the bullet's speed, while the speed of a bullet upon impact focuses on its velocity at the target rather than at the moment of firing. The average speed during flight does not specifically capture the moment of departure from the firearm, which is what muzzle velocity measures. Recognizing this distinction helps in applying knowledge in practical shooting and ballistic analysis.