The Russian AK platform has its roots in World War II in the PPSh41 submachine gun. Mikhail Kalashnikov was impressed by the PPS series and had his own ideas of how to build a better gun. Above all he had three basic design principles: simple, reliable, and inexpensive. The first generation of AKs were manufactured in the Izhevsk Motor Plant number 524 in 1948 but the production was moved to plant number 74 a year later. These early rifles used stamped steel in their receiver and by 1949 the second generation of AKs rolled out, by a design team led by Valeriy Kharkov in the Izhmash Factory, using forged steel receivers. To correct issues with the second generation AKs the third generation, Type 3, was released in 1953 and would go on to become the most common platform of the AK-47.