Ballistics model

As of version 6.1.0 this option has been removed. Given the great speed improvements of computers, there simply is no reason to use the fast but less accurate MAS ballistics model. Rather than offer the option, the program now uses the Krogh™ ballistics model, which is an excellent numerical integration model. The Krogh™ model simulates the flight of the bullet mathematically and accurately deals with variations in the speed of sound, winds from any horizontal direction, multiple ballistic coefficients, and non-horizontal departure.

see Basic Ballistics Theory