What Is Ballistic Coefficient

BC stands for Ballistic Coefficient

Ballistic Coefficient (BC) is a measure of external ballistic performance for bullets. The higher a bullets BC is, the less drop, and wind deflection it will have at all ranges for a given muzzle velocity and environment.

BC is a number that can be used as an input for ballistic solvers to predict trajectories. BC is also used as a selling point for long range bullets so due to this marketing use, sometimes BC’s are inflated or skewed by manufacturers to sell more bullets. As a long range shooter who cares about hitting targets, it’s important to understand the basics of BC so you’re not mislead by marketing hype.

To be more specific, Ballistic Coefficient is a measure of how well a bullet retains velocity as it flies downrange, in comparison to a standard.

BC’s can be referenced to different standards.
The two most common standards in use are:

G1 for old, flat based, blunt nosed bullets
G7 for modern, spitzer nosed, boat tailed bullets

G1 and G7 Ballistic Coefficient

Figure 1.
G1 (left) vs. G7 (right) standard drag models. G7 is much closer to modern long range bullets.

BC’s referenced to the G1 standard are higher numbers, but as you can tell from the image above, not the best representation for modern long range bullets. BC’s referenced to the G7 standard are lower numbers, but are a more accurate representation of a modern bullets drag at all velocities.

The following articles in the “What is a BC?” series will cover many aspects of BC (Ballistic Coefficient) including variation, velocity dependence, marketing influences and many other considerations that long range shooters should be aware of when considering when selecting a bullet for their application.

Want a bullet that has both a high BC and a consistent BC? Learn more about our new Long Range Hybrid Target bullets.

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What is a BC?


What is a BC?


Using BC to Calculate Trajectory


BC and Performance


Measuring BCs


Stability and BC


     Form Factor


     MV-BC Trade-off


     Different Brands

BC Consistency


BC Consistency


Variation in BC with Velocity (G1, G7, etc)


CDMs for ELR


Shot-to-shot Consistency


Sources of BC Inconsistency


Stability


Variations in Bullet Dimensions


     SD of BC, Bell Curve


     BC Variation Reduces Hit % at Long Range


Stability and BC


Comparing BCs


     Form Factor


     MV-BC Trade-Off


     Different Brands

BC, Accuracy, and Precision


BC, Accuracy, and Precision


BC Effect on Accuracy


BC Effect on Precision


     Short Range


     Long Range


Manufacturing Effects on: BC, Accuracy, and Precision

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