The 9×40 Lilja was developed by Erkki Lilja, who was a close colleague of Amio Lahti. He did his own research and development of an assault-rifle type weapon during 1943 and built his own prototype at VKT (Valtion Kivääritehdas = State Rifle Factory), the same place where Lahti also worked developing new weapons for Finnish Military. Just like Lahti he had no official order and mostly funded his own research. Lilja used his own design with an intermediate 9mm cartridge with a 40mm case length. This cartridge resembles a lengthened version of 9 x 19 Parabellum cartridge or a scaled up 30M1 Carbine. This design however suffered the same fate as Lahti’s developments and was never adopted.