This publication, "Mortars" (FM 3-22.90), prescribes guidance for leaders and crewmen of mortar squads. It concerns mortar crew training, and it is used with the applicable technical manuals (TMs) and Army Training and Evaluation Programs (ARTEPs). It presents practical solutions to assist in the timely delivery of accurate mortar fires, but does not discuss all possible situations. Local requirements may dictate minor variations from the methods and techniques described herein. However, principles should not be violated by modification of techniques and methods. The scope of this publication includes mortar crew training at the squad level. The 60-mm mortar, M224; 81-mm mortar, M252; and 120-mm mortars, M120/M121 are discussed, to include nomenclature, sighting, equipment, characteristics, capabilities, and ammunition.