Sectional Density (SD) measures the bullet’s effectiveness on the target. It is calculated by considering the weight and diameter of the bullet. Terminal ballistics, which refers to the effect on the target, is directly related to the SD. Velocity and energy also play a crucial role in enhancing the bullet’s ability to achieve a more effective “knock-down” effect, as well as its ability to penetrate. Generally, bullets with higher sectional density are capable of penetrating deeper.
Sectional density is a crucial factor when selecting a hunting bullet. This is because, when all other variables remain equal, a bullet with a higher Sectional Density will have the following advantages:
Generally, sectional density estimates can help compare penetration performance. Bullets with similar sectional densities, propelled at similar velocities and exhibiting similar expansion percentages, tend to penetrate similar depths.
For instance, let’s consider the following examples:
.30 Calibre (.308″)
– 100gr, SD = .166
– 150gr, SD = .226
– 165gr, SD = .248
.264 (6.5mm) – 140gr, SD = .287
This information can be helpful for those interested in understanding the penetration potential of different bullets, especially when it comes to hunting or other shooting activities.
Remember that higher SD bullets sometimes do not perform well over long distances. The same can be said of high BC bullets, which may not perform well terminally.