Armor - Body and Helmets - Armor for American soldiers. U.S. soldiers in the trenches may soon resember the picture here shown, which illustrates a new type of armor with which the war department experimented in 1917. Bids were asked to furnish helmets, such as this, made of a special alloy steel, 15/100 of an inch in thickness and capable of stopping a rifle bullet. It is made of a series of thin spring steel plates made semiflexible by being sewn together in a canvas sack. This is strapped over the shoulder and around the waist as shown in the picture