Why is it so important to fire at higher angles?

This material briefly explains how the angle of projectile impact affects the effectiveness of enemy engagement due to fragment dispersion. Only conclusions derived from mathematical calculations and practical tests will be presented. Why it is so important to properly configure propellant charges.

Fragment Fields and Methods for Controlling Fragmentation Patterns

During the explosion of a fragmentation munition, a fragment field is created—a stream of fragments characterized by direction, velocity, and density, which is the number of fragments per unit area they cross. The density and velocity of the fragment stream are the most important characteristics that determine the likelihood of hitting a target. Since the target can generally be at any angle relative to the munition’s axis, when solving the problem of determining the probability of fragment hits on the target, it is crucial to know how many fragments are flying in that direction. The answer to this is provided by the so-called fragment dispersion law, which defines the relative quantity and speed of fragments flying in a particular direction relative to the munition’s axis.

One of the most important factors influencing the effectiveness of fragment engagement is the impact angle of the projectile.

The impact angle significantly affects the penetrative power of projectiles. This must be taken into account when firing at armored targets or obstacles, aiming for an impact angle between 50˚ (780 mils) and 90˚ (1404 mils).

The illustration shows that the larger the impact angle, the greater the fragment effect on enemy personnel. This principle is reflected in artillery firing rules, which take into account variable propellant charges.

Mathematically and practically, it has been proven that with an impact angle less than 30 degrees, the fragment effect is minimal, and at 20 degrees, it is negligible. Note two key points:

At low impact angles, effective fragments disperse only to the sides. Thus, overshooting or undershooting the target is ineffective (unless it results in a direct hit).

The effectiveness of engagement decreases up to a 20-degree impact angle and remains constant beyond that point.

Now, it’s essential to understand the relationship between the firing angle (sight) and the impact angle. This relationship does not have direct correlation and depends on the charge, caliber of the gun, type of projectile, weather conditions, and more.

You can check these factors in the “Kropyva” program for different ranges and projectiles.

In general, the impact angle is greater than the firing angle by 25-80%. Since we are primarily concerned with low sights, this value will range from approximately 25-45%.

Examples:

Gun M777, Azimuth 89, Projectile M107, Charge 4 M232A1 — Impact angle = 8˚

Gun M777, Azimuth 131, Projectile M107, Charge 7 M4A2 — Impact angle = 10˚

Gun FH70, Azimuth 198, Projectile M107, Charge 7 M4A2 — Impact angle = 17˚

Self-Propelled Gun 2S1, Azimuth 157, Projectile OF 462, Full Charge — Impact angle = 17˚

These are approximate figures showing that firing with a sight angle below 240 is ineffective.