{"id":5939,"date":"2022-02-23T10:13:46","date_gmt":"2022-02-23T10:13:46","guid":{"rendered":"https:\/\/www.ammoforsale.com\/ammo-club\/?p=5939"},"modified":"2025-11-18T20:29:08","modified_gmt":"2025-11-18T20:29:08","slug":"what-is-ballistic-coefficient","status":"publish","type":"post","link":"https:\/\/www.ammoforsale.com\/ammo-club\/what-is-ballistic-coefficient\/","title":{"rendered":"What is Ballistic Coefficient?"},"content":{"rendered":"

In the simplest possible terms, an object\u2019s ballistic coefficient (BC) is the objective measure of its ability to overcome air resistance in flight. Anything you could name has a BC \u2013 a baseball, a football, a coconut cream pie \u2013 but we most often see the term used to describe how efficiently a bullet can fly through the air.<\/p>\n

A bullet\u2019s BC is typically less than 1 and recorded to the thousandth decimal place (with notable exceptions; the 50 BMG\u2019s BC exceeds 1.000). For example, the G1 BC of a standard 5.56×45 55gr FMJ round<\/a> usually falls at around 0.243. (We\u2019ll get to the meaning of \u201cG1\u201d in a moment.) The G1 BC of a 308 Win 150gr FMJ round is higher at approximately 0.313. The G1 BC of a 224 Valkyrie 75gr FMJ cartridge is even higher at around 0.400.<\/p>\n

The preceding paragraph illustrates the most important thing about BC measurements: the higher the number, the more efficiently the projectile overcomes air resistance in flight.<\/p>\n

How Does Ballistic Coefficient Impact Your Shooting?<\/h3>\n

\"The<\/p>\n

A bullet with a higher BC generates less in-flight drag. This enables it to retain more velocity as it flies farther and farther downrange. The greater the bullet\u2019s velocity, the slower the rate at which it drops. A bullet\u2019s BC thus describes how flat a trajectory it will follow, as well as how hard it will strike its target on impact and how well it can resist wind deflection.<\/p>\n

If you would like to see a demonstration of BC in action, check out this great tool by ShootersCalculator.com<\/a>. We have preset this chart to show the ballistic performance of a heavy .223 cartridge. You can use the tool calculate a good overview of any cartridge\u2019s ballistics. Increase the number in the \u201cBallistic Coefficient\u201d field, and you will notice that the cartridge\u2019s trajectory elevations at 100, 200, 300 and 400 yards all become lower. Decrease it, and its trajectory will have to arch even more in order to reach the 500-yard zero.<\/p>\n

Bullet with .243 ballistic coefficient:<\/strong><\/p>\n

\"Demonstrating<\/p>\n

The same bullet caliber\/weight with .443 ballistic coefficient:<\/strong>\"The<\/p>\n

 <\/p>\n

A bullet\u2019s BC is extremely useful information for rifle shooters who want some estimation of how well a cartridge is going to perform over long distances. It gives an excellent overview of a cartridge\u2019s effective range!<\/p>\n

Once again, every object has a BC, so it only follows that pistol rounds have them as well. That said, the BC of something like 9mm ammo<\/a> or 40 S&W is rarely mentioned because handguns are not generally used for long-distance shooting.<\/p>\n

How Do You Calculate Ballistic Coefficient?<\/h2>\n

A bullet\u2019s ballistic coefficient is the ratio of its sectional density to its coefficient of form. If you want to do a little math, then you can use this formula to calculate a bullet\u2019s ballistic coefficient:<\/p>\n

BC = m\/(d\u00b2((2\/n)\u221a((4n-1)\/n))<\/strong>
\n(m, mass of bullet; d, diameter of bullet; n, number of calibers of the projectile\u2019s ogive)<\/p>\n

If you would rather snort fire ants than try to work through that equation, then you are in luck: JBM Ballistics provides a convenient BC calculator which only requires that you that enter the near velocity (such as the muzzle velocity<\/a>), far velocity (measured at any point throughout the bullet\u2019s trajectory), and distance separating the near and far velocities. Most ammo manufacturers provide at least this much data for their cartridges right on their packaging or website. (You may additionally enter atmospheric data if they are available.)<\/p>\n

If you inspect JBM Ballistics\u2019 BC calculator, you will notice the drag function menu. There is no need to be daunted by so many options, as only two functions are commonly used: G1 and G7.<\/p>\n

What\u2019s the Difference Between G1 and G7 Ballistic Coefficients?<\/h3>\n

\"A<\/p>\n

Let\u2019s preface this explanation by pointing out that not all bullets share the same shape. A bullet with a more aerodynamic profile is quite naturally going to boast a higher BC. A wadcutter, which is cylindrical and has a flat nose, does not have as high a BC as a round nose bullet. A round nose bullet\u2019s profile is less ballistically efficient than a pointed spitzer bullet. Furthermore, a spitzer bullet\u2019s BC is lower than that of an HPBT (the boat tail of which is designed specifically to generate less in-flight drag).<\/p>\n

But if the mathematical formula above demonstrates anything at all, it\u2019s that a bullet\u2019s BC depends heavily on its physical dimensions. For this reason we cannot use the same standard to determine every bullet\u2019s ability to overcome air resistance in flight. This is where projectile shapes come into play:<\/p>\n