The Worst Military Rifle of the 20th Century

If, as the of-stated line goes: "The Mosin rifle fought itself in every major war and lost each time," then the absolute worst rifle of the century had to be this:

The Mauser M98 and its younger brother, the K98:

The 1898 was the principal rifle of Germany through two world wars, both of which were started by Germany and both of which she lost. When the Red Army fought its way into Berlin, the soldiers were carrying Mosin rifles.