In the autumn of 1915, Fedorov was posted as a military observer to France, in the Mont-Saint-Éloi sector. Here he was impressed by the ubiquity of the French Chauchat and by the firepower it brought, but less so about its mobility. According to Fedorov's memoirs, it is here he came up with the idea of introducing into Russian service a weapon with firepower intermediate between the rifle and the light machine gun, but with mobility comparable to a rifle. His decision to adapt his semi-automatic rifle design for this purpose was one of wartime expediency. Fedorov set to the task upon his return to Russia in January 1916. He retained the mechanism of his semi-automatic rifle, with the major addition of a selective fire switch. The fixed magazine was replaced by a curved 25-round detachable box magazine. Due to limited trial nature of its production, most of its parts were custom fitted and not interchangeable, including the magazine. Therefore, in practice, the Fedorov was issued to the troops with only one magazine, which would be reloaded through the breech via standard 5-round Arisaka stripper clips.