A laser range finder that is modular so that it can mounted on different weapon platforms. A pulsed infrared laser beam is reflected off the target. The timed return signal is then used to measure the distance. Another laser, either a visible laser or another infrared laser of differing frequency, is used to place a spot on the intended target. Notch pass optical filters serve to eliminate ambient light interference from the second laser. The range finder using projectile information stored in the unit processes the calculated distance to raise or lower the finder on the weapon. A plurality of weapon platforms and projectile is selected by pressing the desired rubberized keypad. The range finder can-be used with a laser detonated projectile that can be detonated when the projectile is over the target. The projectile is fitted with a detector that is sensitive to the frequency of a wide angle laser beam that is attached to the weapon. Using the range obtained by the range finder, the wide angle laser beam is fired when the projectile is in proper position relative to the target.