The M108 105mm Self-Propelled Howitzer was largely deployed in NATO areas and its ammunition was commonly used throughout NATO forces. Vehicles of this type remain in service in the militaries of some other countries, although it has been withdrawn from service in the US military. The M108 was being phased out of the US Army at the time of Vietnam because its gun was considered too light for battlefield support and 155mm calibre had been standardised in NATO.