Now, as to the Ballistic Codffricient

This is when your will realize that you should have stayed awake in math class. If only. In ballistics, the ballistic coefficient (BC) of a body is a measure of its ability to overcome air resistance in flight. It is inversely proportional to the negative acceleration rate (the rate of slowing due to air resistance): a high number indicates a low negative acceleration—the drag on the vehicle or projectile is small in proportion to its mass (grains).

Huh? It tells us just how efficient a bullet is, how well it cuts through the air to deliver your intent upon the target, be it paper and cardboard, a steel silhouette or what’s for dinner.

BC is what determines the trajectory and any wind drift – other factors (velocity among them) all being equal.

And it is determined most by the shape of the bullet and the speed (velocity is always king!) at which the bullet is traveling, while the sectional density of an object obviously does not change. Sectional density being the ratio of a bullets diameter to its weight, the numerical result of a calculation that compares a bullet’s weight in grains to its diameter. To calculate a bullet’s sectional density, divide the bullet’s weight by its diameter squared.

Common sense tells us a pointed projectile is a more efficient shape than a round nose or a flat nose, or a ball/sphere at cutting through the air. On the trailing side of a bullet a boat tail reduces the drag more effectively as compared to a flat untapered base. Just look at 18-wheelers on the highways these days, most have four (4) “wings” that come out and taper across the rear doors of the trailer to produce a boat-tail shaped end to reduce drag and turbulence and improve fuel efficiency; this is also the application of BC being used to get the maximum out of the energy being consumed to move a vehicle through the air. And when you compare the BC of some common bullets, for example, a 22 (.224) 52 grain, has a BC of .253 while a .308 (.30) 168 grain round has a BC of .480 you can see that the larger bullet (heavier) has the superior BC and is better at cutting through the air and delivering more energy to your intended target.

There are a lot of useful resources on-line that discuss the ballistic coefficient of projectiles, something one should investigate when looking for a rifle/bullet combination for long range accuracy factoring in just what the intended target ultimately will be. It will take some research as the BC of rounds is not something normally listed on the box.

While BC is important and something to be known before you purchase your weapon of choice remember that your ability to get good bullet placement comes from practice with the rounds you have chosen and is the real determining factor in your success. Be safe, know your weapon, practice with your chosen round and avoid the temptation to use lesser rounds at the range; chose a round that you can become proficient with and depend on for any target.