Aimo Lahti Aimo Johannes Lahti ( April 28 , 1896 – April 19 , 1970 ) was a self - taught Finnish weapons designer . Out of the 50 weapons that he designed , the best known is the Suomi M - 31 SMG . Other well - known weapon designs include the Lahti - Saloranta M / 26 LMG , Lahti L - 35 pistol and Lahti L - 39 anti - tank rifle . Lahti also designed the 7 , 62 ITKK 31 VKT anti - aircraft machine gun and the 20 ITK 40 VKT anti - aircraft cannon . His work is considered decisive in defending Finnish independence and increasing trust in the reliability of domestic weapons produced there . Biography . Early years . Aimo Lahti was born in Viiala in 1896 , to a family of five . He had a safe and somewhat wild childhood . Lahti did not enjoy school and left after the 6th year of elementary school . He started working in the Viiala glass factory when he was 14 years old . In the same year , he bought his first weapon , a Berdan rifle , with five marks he had earned in the factory . Lahti was fascinated by the rifle ’ s mechanism and visited local gunsmith " Säteri " with whom he examined the weapon closely . Aimo Lahti visited him several times , becoming familiar with weapon mechanisms . He served his conscription in central Finland ’ s regiment during 1918 and 1919 . On October 20 , 1919 he married his wife , Ida , with whom he had his only child . His son , Olavi Johannes Lahti , was later a pilot in the Finnish Air Force and died in 1944 . Master Armorer in the Finnish Army . After working for the railway ; he joined the Finnish Army as a Master Armorer in 1921 . He was influenced in this decision by Captain Rosenholm . In 1922 — he started to design the Suomi M - 31 SMG after examining the Bergmann MP18 , which had many design problems as well as being expensive . The new design was revolutionary because the reliability , accuracy and the rate of fire were excellent . The first 200 Suomi SMGs were produced in 1922 . After the prototypes were made , he was ordered to work under the control of the Ministry of Defence and to design a light machine gun , which eventually would be the Lahti - Saloranta M / 26 . He then improved the Mosin Nagant rifle by designing the M / 27 " Pystykorva " ( " Spitz " ) , which later was issued to the Finnish Army as their service rifle . In 1932 Lahti and the Ministry of Defence signed two important agreements about Lahti ' s earnings and other economic benefits . It also gave the government rights to use and sell his designs . In the same year , he got an offer to move to an American weapon company . He was offered a check for 3 million marks and a 5 % commission on the weapons that would have been produced in the USA . On the same day the Ministry reformed his older contract . Lahti received more benefits and rights to his inventions and therefore did not feel that moving to the USA was a better offer . Aimo Lahti continued to design weapons until the end of the Continuation War when the Allied Control Commission questioned him about the lost 30 " assault rifle s " that he was designing and other topics . The commission made a decision that he would not be allowed to work as a weapon designer anymore . He enjoyed a Finnish Army ’ s Major General ’ s pension for 50 years , until his death in 1970 in Jyväskylä at the age of 74 .