In 1890-1900 an Italian officer made the first assault rifle. Most of it's functions where finished between 1903 and 1911. In the end it had: selective fire capabilities, single shot, and burst, intermediate-powered ammunition, and also as the first successful implementation of gas operation in a rifle. The rifle fired 6.5 x 52 Mannlicher-Carcano ammunition fed from a 25-round detachable box magazine.
Now this gun was considered unreliable, for what reasons I am unsure, I think it was for misfires. But WI Amerigo Cei-Rigotti worked on improving this gun so it could be used in the field?
What affect would such a rifle have on WWI?