Ballistic coefficient of 7mm PRC — what impacts it?

Factors Affecting Ballistic Coefficient

The ballistic coefficient of the 7mm PRC is primarily affected by the bullet’s shape and size, particularly its ogive and boat tail, which reduce drag and improve aerodynamics. A well-designed bullet with a high ballistic coefficient can maintain its velocity and trajectory over long ranges. For example, the 140-grain Hornady ELD-X bullet has a ballistic coefficient of 0.646, while the 120-grain Nosler Ballistic Tip has a ballistic coefficient of 0.555.

Bullet Construction and Weight

The construction and weight of the bullet also impact its ballistic coefficient. A bullet with a higher density and a heavier construction will generally have a lower ballistic coefficient due to increased air resistance. In the case of the 7mm PRC, a lighter bullet with a lower density, such as the 120-grain Berger VLD, may have a slightly higher ballistic coefficient than a heavier bullet like the 140-grain Nosler AccuBond.

Rifle Specifications and Environmental Factors

The rifle’s barrel length and twist rate can also affect the ballistic coefficient of the 7mm PRC, particularly at longer ranges. A longer barrel and a faster twist rate can help stabilize the bullet and maintain its velocity, while environmental factors such as wind and temperature can also impact the bullet’s trajectory. To mitigate these effects, hunters can use a ballistic calculator or consult with a ballistician to determine the optimal bullet and rifle specifications for their specific hunting needs. For example, a hunter planning to shoot at elk at 400 yards may prefer a bullet with a higher ballistic coefficient, such as the 140-grain Hornady ELD-X, while a hunter shooting at closer ranges may opt for a lighter bullet with a lower ballistic coefficient, such as the 120-grain Nosler Ballistic Tip.