A boresight apparatus and methods for use of same with a gun system are provided. The gun system includes a gun tube and a pointing device. The boresight apparatus is installed on an outside surface of the gun tube. Once the gun tube is adjusted to a desired gun-tube orientation, the boresight apparatus determines the gun-tube orientation, including an azimuth, an elevation, and a roll of the gun tube. The pointing device determines a pointing-device orientation at the desired angle. The gun system may be boresighted by adjusting the pointing device based on the gun-tube orientation. The pointing accuracy performance of the gun system may be determined based on offsets between the gun-tube orientation and the pointing-device orientation. The boresight may determine an azimuth using optical technologies, such as lasers, with a precision survey or using north-finding techniques with gyroscopes.