Which factor has a significant impact on a firearm's maximum projctile range?

The maximum projectile range of a firearm is significantly impacted by the angle of elevation at which the projectile is launched. An optimal angle, typically around 30 to 45 degrees, maximizes distance due to the balance between vertical and horizontal velocity components. Additionally, factors such as projectile speed, air resistance, and environmental conditions (like wind and altitude) also play crucial roles in determining the effective range.