As stated above, the accuracy of the ballistic solution is only as accurate as the inputs you give it. The advertised BC’s for Berger bullets are established by actual field firing tests over long range and are very accurate. Using the properly referenced BC (G7 vs G1) for the bullet you’re modeling is important. For any bullet with a boat tail, we recommend using the G7 BC. Flat based bullets have a drag profile that matches the G1 standard better. The products page lists both values for each bullet, with the recommended value highlighted.
Knowing your true muzzle velocity is important when calculating external ballistics. It’s best to measure your muzzle velocity directly with a chronograph.
Air pressure considerations
Air pressure considerations
If you want a truly accurate long range trajectory prediction, you can’t ignore atmospheric effects. This is especially true the farther you get from standard conditions (sea level altitude, 59 degrees Fahrenheit, 0% humidity). If you want a valid trajectory for high above sea level, you need to enter an air pressure that corresponds to your altitude. You can see a table of air pressure by hovering the mouse on the word ‘Pressure’ in the ballistics program.
Last but not least, it’s important to verify the most important link between the calculated ballistics and your point of impact: your scope. If the ballistics program calculates 30.0 MOA of drop for a particular shot, and you dial your scope to 30.0 MOA, are your sure it’s applying exactly 30.0 MOA? In reality, many scopes have enough error in them to cause misses at long range. It’s important to verify the actual value of your scope clicks by firing groups at short range. Shoot a group at your rifle’s zero, adjust the scope a known amount and shoot another group. Measure the distance between the two groups to see if the scope actually moves your point of aim by the desired amount. If it doesn’t, you need to apply a correction factor to your scope in order for the output from the ballistics program to be accurate for your particular scope.
