THEROY BEHING THE PROJECTILES TRAJECTORY IN RIFLE

 

Theory Behind the Trajectory of Projectile

A bullet ascends from a rifle after being fired due to the physics of projectiles motion and the initial angle at which the rifle is aimed. When we fired from a gun, it initially travels in the direction the barrel is pointed. The trajectory of the bullet, however, is influenced by several factors, causing it to ascend or appear to rise before eventually descending back to the ground.

1.      Barrel Angle and Line of Sight:

·        Barrel Angle: When a shooter aims a gun, they typically align their sights with the target. The barrel of the gun is often angled slightly upward relative to the shooters line of sight. This upward angle causes the bullet to ascend initially after leaving the barrel.

·        Line of Sight: The line of sight is the straight line along which the shooter aims, but since the barrel is angled upwards, the bullet must first rise to intersects this line before descending.

 

2.      Forces Acting on the Bullet:

·        Muzzle Velocity: This is the speed at which the bullet exits the barrel. The higher muzzle velocity, the more energy the bullet has to travel upwards before gravity starts to pull it down.

·        Gravity: Gravity constantly acts on the bullet, pulling it downward. The upward angle of the barrel gives the bullet an initial upward trajectory, but gravity will eventually cause the bullet to curve downwards.

·        Air Resistance: As the bullet travels, it encounters air resistance, which slows it down. However, this force is not significant enough to prevent the bullet from rising initially when fired at an upward angle.

 

3.      Ballistic Trajectory:

·        Initial Ascent: The bullet rises initially due to the combination of the upward angle of the barrel and the high muzzle velocity. The bullet continues to ascend until the forces of gravity and air resistance overcome the upward momentum.

Or

The barrel is slightly angled upward relative to the line of sight (Line of Bore or Line of Barrel). When the bullet exits, it initially travels upwards relative to the line of sight due to this angle, even through gravity is pulling it downward from the moment it leaves the barrel. This initial upward movement is what creates the bullets ascending trajectory.

 

·        Apex: The highest point in the bullet’s trajectory is called the apex. After reaching the apex, gravity becomes the dominant force, causing the bullet to descend.

·        Descent: After the apex, the bullet begins to fall back towards the earth eventually striking the target (if aimed correctly) or to the ground.

 

4.      Practical Implications:

·        Shooting Distance: At closer ranges, the bullet rise may be minimal, and it might seem to travel in straight line. However, at longer distances, the bullets arc becomes more pronounced, and shooters must account for this when aiming.

·        Sighting and Zeroing: Firearms are often zeroed at specific distance, meaning the sights are adjusted so that the bullet will strike where the shooter aims at that distance. Beyond this distance, the shooter must account for the bullet’s trajectory, adjusting their aim higher or lower depending on the range.

Key Points Related to The Trajectory of a Bullet in Rifle Sight:

1.      Line of Sight and Line of Bore:

·        Line of Sight (LOS): This is the straight line along which you are looking when you aim through the rifles sight whether using iron sights or an optical scope. It represents the intended path to the target.

·        Line of Bore: This is the straight line that extends from the centre of the rifles barrel. The bore line is typically angled slightly upward relative to the line of sight to compensate for the bullets drop due to gravity.

 

2.      Ascending Phase:

·        As the bullet exits the barrel, it initially starts to rise relative to the line of sight. This happens because the line of bore is angled upwards, causing the bullet to rise above the line of sight. Despite gravity acting on the bullet, the initial upward angle of the bore allows the bullet to ascend to a point higher than the line of sight.

 

3.      Culminating Point or Apex:

·        This is the highest point in the bullet’s trajectory. After the bullet has crossed the line of sight and continued to rise, it eventually reaches its peak height. At this point, the bullets upward momentum decreases to zero, and it starts to descend. The apex is influenced by factors such as the bullets velocity, the angle of departure, and external conditions like air resistance.

 

4.      Descending Phase:

·        After reaching the culminating point, the bullet begins to fall due to gravity. As it descends, it will cross the line of sight for the second time. This second crossing is often referred to as the far zero. Beyond this point, the bullet will continue to fall below the line of sight as it moves farther from the rifle.

 

5.      First Catch and First Grace:

·        First Catch: This term refers to the first point where the bullets trajectory intersects the line of sight. This usually occurs shortly after the bullet leaves the barrel and begins to ascend. The catch is where the bullet first reaches the same height as the line of sight.

·        First Grace: This term refers to the second intersection of the bullet’s trajectory with the line of sight, occurring after the bullet has passed the apex and started descending. The grace is where the bullet, on its downward path, again aligns with the line of sight.

 

6.      Point of Aim:

·        Point of Aim: This is the exact spot where the shooter is aiming, as seen through the sights. It is ideally where the bullet is expected to strike, depending on the distance to the target and the rifles zeroing.

 

7.      Point of Impact:

·        Point of Impact: This is the actual location where the bullet strikes the target. If the rifle is properly zeroed, the point of impact should coincide with the point of aim at the designated zeroing distance. However, due to bullet drop, wind, and other factors, the point of impact can deviate from the point of aim at different ranges.

 

8.      Danger Zone:

·        This is the range over which the bullet’s trajectory stays within a certain vertical distance (usually defined as a few inches) above or below the line of sight. Within this zone, the bullet is likely to hit the target even if the exact range is slightly misjudged. The danger zone is crucial in combat and hunting scenarios because it maximizes the likelihood of a hit without precise range estimation.

Or

The danger zone in the trajectory of a bullet refers to the area where the bullet can cause harm. It is the space along the bullets path, from where it is fired to where it might land or stop, with which the bullet has enough energy to injure of kill. This zone includes the initial path of the bullet as it leaves the gun and the area where it might ricochet or travel further after impact.

 

The danger zone is not just vertical it is a 3D area. It includes the space above and below the bullet’s trajectory as well as along the path it travels. This area encompasses the entire volume where the bullet could potentially hit or cause damage, considering both its initial flight path and any potential deviations.

9.      Beaten Zone:

·        This term is often used in military contexts to describe the elliptical area on the ground     where bullets fired from a machine gun or rifle will impact. For a single bullet, the beaten zone would refer to the area within which the bullet might land, given factors like bullet drop and dispersion. It generally refers to the area where the bullet will strike once it descends below the line of sight.

 

10.   Angle of Attack:

·        The angle of attack in a bullet’s trajectory refers to the angle at which the bullets path intersects the target relative to the line of sight or the trajectory path. It describes how the bullet’s trajectory is oriented in relation to the target when it impacts.

In simpler terms it is the angle between the bullet’s trajectory and the horizontal plane or the line of sight. This angle can affect how the bullets path changes over distance due to the factors like gravity and air resistance.