The decision by the Ministry of National Defence to introduce Mauser repeating rifles into the armaments of the new Czechoslovak Army inspired Lieutenant Rudolf Jelen (1876–1938) to propose modifications to the M 1912 rifle , manufactured before the war by the Austrian arms factory in Steyr for Mexico. The modifications suggested by Jelen were not limited to improvements to the weapon, but also included a patent-protected bayonet. The first specimen of rifles made according to his design were produced by the Brno arms factory in 1919, and in March 1921 the Ministry of National Defence ordered the production of 300 rifles of 7.92 mm Mauser and 7 mm Mauser calibre, including bayonets, half of which were sent for testing to the Kingdom of Yugoslavia (from October 1929, Yugoslavia). Tests with the other half of the Mauser-Jelen rifles were conducted in the first half of 1922, but the reports from the various units in Bohemia and Moravia did not favour the Jelen design, so the Ministry of National Defence lost interest in it.