Complex sentence: The original GRD-40 grenade has been replaced by a series of grenades designed for use at different ranges; these are the GRD-50, GRD-100 and GRD-200 for use at 50,100 and 200 meters respectively.
Split into simpler sentences: The original GRD-40 grenade has been replaced by a series of grenades designed for use at different ranges. These are the GRD-50, GRD-100 and GRD-200 for use at 50,100 and 200 meters respectively.