Which factor greatly influences a firearm's maximum projectile range?

The maximum projectile range of a firearm is significantly influenced by altitude because of the changes in air density at different elevations. At higher altitudes, the air is less dense, which reduces the drag acting on the projectile as it travels through the air. This decreased resistance allows the projectile to maintain its velocity longer, resulting in a greater range compared to firing at lower altitudes.

Other factors, while they may affect aspects of shooting or ballistics, do not have as pronounced an impact on the maximum range of a projectile. For instance, temperature can influence the speed of sound and the viscosity of the air, but it is not as directly related to the range as altitude. Similarly, weather conditions, such as wind, can affect the path of a projectile but do not fundamentally change the physics of its potential range. The choice of quarry is more about hunting practice and ethics rather than the physics of the firearm itself. Therefore, altitude emerges as a critical factor in determining how far a projectile can travel.