A WWII era Bancroft manufacturer officers cap with Army pin.

Early in World War II the U.S. forces were still equipped with the M1917/M1917A1 "Doughboy" helmets that were left over from world war one. In 1941, the M-1 "steel pot" helmet was adopted as a replacement in the armed services, although it did not become universal for at least another year.

The M-1 Steel Helmet became the symbol of U.S. military forces and was used world wide by all branches of the services for the duration of World War II, Korea, and through the Vietnam War.

Several distinct characteristics can be noted to help determine the age of an M-1 helmet. The World War II examples will  have a seam in the front whereas those produced post-war will have the seam in back. The seam that is being referenced is located around the rim of the helmet. Also, early production helmets are found with fixed bales. It was not until 1943 that a swivel bale was introduced. 

The M-1 helmet and liner in the pictures above is a typical example from the Viet-Nam era. The cloth cover was designed with a disruptive camouflage pattern and was reversible with either leaf patterns in green or brown for operations in different terrain. A close inspection of the left photograph will show small slots in the cloth cover for inserting natural foliage. In this same photograph a helmet band can also be seen. This band was designed to hold foliage but was more commonly used to hold cigarettes, insect repellent, and so on during the Viet-Nam era.

An M-1 helmet on display. At the left is a 20mm German WWII round, on the right is an M1A2 grenade adapter, behind them is a box of 8mm German K98 ammunition and on the right is two different pairs of German WWI binoculars.