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Effects on Ballistic

This category contains 8 posts

Temperature Effects on Zero

Sgt G. Roberts For over three hundred years man has endeavored to find his target with the first shot from his rifle, whether it be man or beast, in conflict or at peacetime. This skill in the art of marksmanship is one of the most pondered and talked about subjects in the Military & Law […]

Eotvos effect

The Eotvos effect is caused by the rotation of the earth, but this is not to be confused with the Coriolis effect. While Coriolis is related to the effects caused by the earth, it is on a horizontal plane. Eotvos effect is a vertical change in target position that at long distances could cause a […]

Transonic Problem

When the velocity of a rifle bullet fired at supersonic muzzle velocity approaches the speed of sound it enters the transonic region. In the transonic region, an important thing that happens to most bullets, is that the centre of pressure (CP) shifts forward as the bullet decelerates. That CP shift affects the (dynamic) stability of […]

Vertical angles

The vertical angle (or elevation) of a shot will also affect the trajectory of the shot. Ballistic tables for small calibre projectiles (fired from pistols or rifles) assume that gravity is acting nearly perpendicular to the bullet path. If the angle is up or down, then the perpendicular acceleration will actually be less. The effect […]

Ambient air density

Air temperature, pressure, altitude and humidity variations make up the ambient air density. Decreased air density will result in a decrease in drag, and increased air density will result in a rise in drag. Humidity has a counter intuitive impact. Since water vapor has a density of 0.8 grams per litre, while dry air averages […]

Wind

Wind has a range of effects, the first being the effect of making the bullet deviate to the side. From a scientific perspective, the “wind pushing on the side of the bullet” is not what causes wind drift. What causes wind drift is drag. Drag makes the bullet turn into the wind, keeping the centre […]

Coriolis effect

The coordinate system that is used to specify the location of the point of firing and the location of the target is the system of latitudes and longitudes, which is in fact a rotating coordinate system, since the Earth is constantly rotating. For small arms, this rotation is generally insignificant, but for ballistic projectiles with […]

Spin drift

Even in complete calm air, with no sideways air movement at all, a bullet will experience a spin induced sideways component. For a right hand (clockwise) direction of rotation this component will always be to the right. This is because the bullet’s longitudinal axis and the direction of the velocity of the center of gravity […]