THEORY BEHIND WHY IN CLOSE RANGES AND BEYOND LONG RANGES THE PONT OF IMPACT IS BELOW THE POINT OF AIM

 

Theory Behind Why in Close Ranges and Beyond Long Ranges the Point of Impact is Below the Point of Aim

Let us discuss practically above from the picture:

 

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.

 

 

 

 

      I.          IN CLOSER RANGES (100 METERS):

 

As closer ranges, the point of impact can be below the point of aim. This phenomenon is primarily due to the relationship between the line of sight which is typically through the sights or optics of the weapon, and the trajectory of the bullet, as well as the height of the sights or optics above the bore axis the line through the centre of the barrel.

 

1.      Line of Sight and Bore Axis:

·        Line of Sight: When you aim a firearm, you align the sights or use an optic, which creates a straight line of sight toward your target. This line is typically parallel to the ground or the intended target plane.

·        Bore Axis: The bore axis is the imaginary line running through the center of the barrel. When you fire, the bullet travels along this axis initially but the follows a parabolic trajectory due to gravity.

 

2.      Height Over Bore:

·        The sights or optics on a firearm are usually positioned above the barrel. This distance between the line of sight and the bore axis is known as the height over the bore.

·        At very close ranges within a few yards or meters, the bullet has not traveled for enough to rise significantly above the bore axis which it needs to do the intersect the line of sight at the point of aim. Therefore, the bullet will impact below the point of aim, corresponding to the height over bore.

 

3.      Trajectory and Zeroing:

·        Zeroing: When you zero a firearm, you adjust the sights or optics so that the bullet hits the point of aim at a specific distance. For example, if a rifle is zeroed at 100 yards, the bullets trajectory will intersect the line of sight at that distance.

·        Trajectory: Bullets follow a curved path trajectory due to gravity. After the bullet leaves the barrel, it initially travels below the line of sight at the zeroed distance, and then begins to drop again as it travels further.

·        At close ranges, because the bullet has not yet risen to intersect the line of sight, it will impact below the point of aim.

 

Let us see an example:

Your rifle is zeroed at 500 Meters, the bullet trajectory and line of sight will exactly intersect at 500 meters that is mentioned in the figure as first grace. Also, in the intersection of point of aim and point of impact will exactly meet in 500 meters.

But you are trying to shoot the targets in the 100 meters. What will happen is the line of sight and bullet trajectory will not intersect with in the 100 meters, and the bullet has not yet risen to intersect the line of sight, it will impact below the point of aim.

According to figure if you try to shoot the target in 200 meters, the bullet will hit the point of aim in 200 meters, or the point of aim and impact is in same point in 200 meters because the bullet trajectory and line of sight will intersect exactly in 200 meters. And the 200 Meters is the first zeroing point.

    II.          AT INTERMEDIATE RANGES (350 METERS):

 

At intermediate ranges the point of impact can be above the point of aim. This phenomenon is primarily due to the relationship between the line of sight which is typically through the sights or optics of the weapon, and the trajectory of bullet.

 

1.      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.

 

Let us see an example:

Let as assume your rifle is first zeroed at 200 meters and the second zeroed at 500 meters. The point of aim and the trajectory of bullet will exactly meet in 200 meter is known as first zero and 500 meter is known as second zero.

But you are trying to shoot the target between the 200 and 500 meters that is 350 meters. In the 350 meters the bullet goes to its peak highest elevation and it descends due to gravity. So, the bullet hit above the point of aim because of the elevation of the projectile, that is known as culminating point or Apex.

 

  III.          AT LONG RANGES (500 METERS):

At the long ranges the line of sight and the bullet trajectory will intersect each other, so in long ranges the point of impact is exactly on the point of aim.

 

 

1.      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.

·        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.

 

Let us see an example:

Let us assume your rifle is first zeroed in 200 meters and the second zeroed in 500 meters. In the first zero and the second zero the line of sight and the bullet trajectory will intersect each other. Also, the descending phase will occur after the culminating point or Apex, also the first grace will occur in the exact meeting point of the line of sight and the trajectory in the second zero point that is known as first grace. So, the point of impact is exactly on the point of aim.

 

  IV.          BEYOND LONGER RANGES:

 

1.      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.

When the bullet losses its kinetic energy and the velocity it falls towards ground due to the effect of gravity. And after the second zero or first grace the bullet falls down towards the ground.

 

Let us see an example:

Let us assume your rifle is first zeroed in 200 meters and the second zeroed in 500 meters. In the first zero and the second zero the line of sight and the bullet trajectory will intersect each other. Also, the descending phase will occur after the culminating point or Apex, but you are trying to shoot the target after 500 Meters or the target after the second zero, what should happen is the bullet hit below the point of aim because of the gravity and trajectory of the bullet because the second zero is at 500 Meters but you are trying to shoot the target in 750 meters .

 HOLD OVER IN LONG RANGE SHOOTINGS:

In long range shooting, holdovers refer to the practice of point of aim above the target to compensate for the bullets drop due to gravity over a long distance. As a bullet travels farther from the muzzle, gravity pulls it downward, causing it to fall below the line of sight. The farther the target, the more the bullet will drop, requiring the shooter to adjust their aim to ensure the bullet hits the target.

 

Hold over is typically expressed in terms of minutes of angle (MOA) or milliradians, which are angular measurements that describe how far the point of aim should be raised above the target. Shooters often use reticles in their scope that have markings such as hash marks or dots to help them estimate and apply the correct amount of holdover for a given distance.