Abstract: In a device and method for predicting a future muzzle velocity of an indirect fire weapon 3, 7 means 9, 11 responsive to a measurement of muzzle velocity are adapted to implement an adaptive empirical prediction method to predict the future muzzle velocity. The invention also relates to an aiming system and method for an indirect-fire weapon 3, 7. The system comprises a muzzle velocity measuring device 5, and predictor means 9, 11 responsive to an output of the muzzle velocity measuring device 5 for determining a new elevation setting from the weapon. Preferably, the predictor means utilizes an adaptive empirical prediction method such as a Kalman Filter or neural network.