Secretly Short Sighted

This is the Italian Perino machine gun. It was created in the early 1900s by an Italian army officer. It had two features that were fairly revolutionary: 1) it was strip fed, but the strips were held in the box on the left of the gun, so the assistant gunner could keep feeding the gun without having to change any belts. 2) the cartridges, once fired, were put back on the strip and then the whole thing was spit out of the gun. These two things made the gun very ahead of its time and it could have been incredibly successful.

However, instead of running it in trials in competition with other machine guns, the Italians kept it totally secret. It wasn't ready in time to be adopted for WWI, and therefore never saw the light (and its rightful place was taken by the less-than-stellar FIAT-Revelli M1914).