External ballistics

External ballistics

1. External Ballistics

2. Submitted to- Ketan Sir Submitted By- Khirad Sayyed

3. External Ballistics External ballistics deals with motion of projectile or bullet from the muzzle end of the weapon, to the target or till it drops down under the influence of gravity’ The trajectories of projectiles are parabolic in form, but would differ in curvatures and length.

4. Factors Affecting E xternal B allistics Trajectory means the path of the bullet from muzzle to the striking point on the target and it is in the form of parabola. The flight of all projectiles whether through the air or in vacuum without and air resistance is governed by newton’s law of motion. Many factors influence the flight of the bullet, but the two main factors are gravitational pull of the earth, which brings it to the ground or target, and resistance of the air which reduces its velocity.

5. Trajectory Of A B ullet I n V accum Let a bullet be fired from a firearm in the direction OZ at an angle alpha with horizon with a velocity V. I f there is no factors influencing the initial velocity V like air resistance and gravitational pull of the earth as can happen in space, the projectile would travel in a straight line covering equal distances in every second. According to newton’s first law of motion, a body at rest or in motion would continue to be in that position unless some external force is applied to change its position.

6. Air resistance will decrease the velocity of bullet and gravitational force will pull down the bullet. Therefore, bullet will achieve parabolic path. The positions of the bullet are different in case of vacuum firing. When the external factors such as air resistance and gravitational force takes place, it will change the positions of the bullet and path of the bullet. As air offer resistance to the bullet and decreases the velocity and hence the distance travelled would be lesser, giving rise to new positions. Gravitational pull will bring the bullet downwards whose trajectory forms a parabola’

7. Ballistic Coefficient Ballistic coefficient is usually represented by C and indicted the ability of the projectile to overcome air resistance, and its efficiency in flight. C = W/id** Larger the ballistic coefficient, the better the bullet retain its velocity and lower the bullet drop for any given substance. B ullet drop- The effect of gravity on a projectile in flight is often referred to as bullet drop.

8. Factors affecting trajectory of a bullet Velocity of projectile- S ince the velocity of projectile is the most important factor affecting the shape of the trajectory. Greater the velocity, flatter will be the trajectory. Advantages of flat trajectories- It reduces deflection of projectile. it reduces barrel time. The effective shooting range is increased as the errors in the estimation of distance are reduced .

9. Spin of bullet- R evolving of bullet around its longitudinal axis or gyration. Bullet spin reduces air resistance which results in reduction in loss of velocity. Speed of spin and twist motion- The degree of the turning of bullet is called twist. The length in which projectile completed its one turn is called as twist. And the twist is depend on the diameter, length, and density of projectile.

10. Angle of fire- The angle at which barrel axis lines with the base line. Generally it is low. The angle of elevation at which maximum range is attain is called critical angle. Yaw and stability- Yawning of bullet is the deviation of bullet in its longitudinal axis from the straight line of flight. Drift- It is caused by action of wind on the bullet.

11. Skin resistance- The skin resistance occur due to interaction of air and matter molecule. it is of small quantity Temperature - Deviation from standard daytime temperature (59 degrees Fahrenheit/15 degrees Celsius) affects bullet trajectory. Thus the trajectory of bullet varies in accordance with temperature.

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