Secant Ogive refers to a specific shape or profile of a bullet's nose which helps it to have a higher BC “Ballistic Coefficient” and lower drag.
A secant ogive produces better BC because of the slightly ‘sharper’ angle of the projectile tip, as opposed to a more rounded tangent ogive, which has other benefits.
Understanding this concept requires a dive into bullet design and aerodynamics:
The ogive is the curved portion of a bullet that defines its nose or forward profile.
The secant ogive is a type of ogive shape that's derived from a segment of a circle that intersects the circle's circumference at two points, resulting in a more pronounced, elongated curve compared to other ogive designs.
Compared to Tangent Ogive
The other common ogive shape is the tangent ogive, which has a curve that is tangential to the bearing surface of the bullet, resulting in a smoother transition.
In contrast, the secant ogive is "steeper" and is less rounded, often giving the bullet a sharper, more pointed appearance.
The secant ogive design can offer superior aerodynamic properties. This shape can reduce drag, leading to a higher ballistic coefficient (BC), which means the bullet retains velocity better, has a flatter trajectory, and is less affected by wind.
For long-range shooting, where aerodynamics plays a critical role in bullet performance, bullets with a secant ogive design are often preferred.
Considerations in Reloading
When handloading or reloading ammunition, the bullet's ogive shape, whether secant or tangent, can influence how the cartridge is seated. The specific shape might affect the overall length of the loaded cartridge and how it interacts with the rifling in the firearm's barrel.
Due to its aerodynamic benefits, the secant ogive design is popular in many modern long-range bullets, especially those intended for precision shooting, hunting at extended ranges, and competitive long-range disciplines.
Not all firearm barrels might be optimized for bullets with a secant ogive design. Some might prefer tangent designs or hybrid designs that combine elements of both. Hence, shooters often experiment to determine which bullet shape provides the best accuracy and performance in their specific firearm.
In essence, the secant ogive is a design element in bullet shaping that focuses on improving aerodynamic efficiency.
In the realm of precision and long-range shooting, the nuances of bullet design, like the ogive shape, can have significant impacts on performance.