![average speed of a bullet average speed of a bullet](https://cdn4.explainthatstuff.com/bullet-energies-compared.png)
Shorter flight times mean gravity is acting on the bullet for less time and thus results in less drop. Gravity is a constant force acting on the bullet while in flight. Similarly, gravity also begins to act on a bullet as it leaves the barrel. As a result, higher initial velocities will reduce time of flight and thus drift. The time of flight is also important because the longer the bullet is in motion the more time wind forces are pushing the bullet thus increasing drift. It is noteworthy that cross-sectional area is a component in calculating ballistic coefficients. A larger cross sectional area results in more surface area for wind forces to act on and thus will impart more force on the projectile. With regards to wind vectors, atmospherics as well as the cross-sectional area and time of flight will influence the drift of the bullet. Said differently, at higher velocities, there is more air resistance acting on the bullet and this force decreases as velocity decreases. Additionally, air resistance is a function of velocity and in laminar flow conditions the air resistance force is proportional to the velocity. The more dense the air the more resistance will be encountered by the bullet. The geometry or shape of the bullet will also have an effect on the amount of air resistance encountered. Atmospheric conditions such as density influence the amount of air resistance acting on a projectile. Air resistance is a force acting in the direction opposite to relative motion of the bullet and acts to slow the velocity of the bullet. The initial velocity (Vo) of a projectile as it exits the muzzle of the firearm is critical variable in kinematic equations of motion as it has a significant effect on the trajectory of the bullet with respect time of flight to target, drop, drift and kinetic energy.Īs the bullet exits the barrel, forces such as air resistance, wind vectors (direction) and gravity begin to influence the trajectory of the bullet. The velocity of the projectile as it exits the barrel is referred to as the initial velocity commonly denoted as Vo. When the bullet exits the barrel it is at its maximum velocity. The firing pin strikes the primer igniting the propellant charge which accelerates the projectile through the length of the barrel. It is important to consider why projectile velocity is important for long range shooting. While a standard deviation is a useful statistical measure, it is important to understand what the number really means and the requisite data necessary to make valid causal inferences from a standard deviation.īefore delving into the technical details of standard deviations. Unfortunately, standard deviations are commonly misinterpreted and applied in mathematically incorrect ways. The standard deviation of projectile velocity is one of the most widely cited performance metrics for long range precision shooting.