isochronX is the first ever app that computes bullet ballistic coefficient from shooting range data. Just input muzzle velocity, environmental data, and bullet drop at different ranges, and isochronX will compute the G1, G2, G5, G6, G7, and G8 ballistics coefficients for your projectile. It will also indicate the order in which the different G-models are best suited to your projectile.

Notes for use:

All available pages must be visited before the BC can be computed etc.

Accurate environmental data is a must for accurate results.

At least one point should be entered beyond the muzzle that is around 100 yards or less from the muzzle for accurate initialization.

Enter at least two data points past the muzzle. Range has default increments of 100 yards, but any increments can be used. Note that not all available trajectory data fields need to be entered. Please provide any feedback or questions to [email protected].

You can enter negative numbers from a phone by holding down the ‘.’ key until the negative sign key comes up.

Drop data is positive up, so a “drop” that is above zero must be entered as a positive number. For example, a 110 grain VMax with 2.4" sight height and 200 yard zero might have the following data:

Distance (yards), Drop (inches)
0,-2.4
100, 2.5
200, 0.0
300, -10.40
400, -30.60
500, -62.80

Please provide any feedback or questions to [email protected].