Introduced in 1952 as Chief's Special Airweight. Initially had an alloy frame and cylinder. In 1954, following many complaints regarding damaged revolvers, cylinders were made of steel. Barrel lengths, finishes and grip options on Airweight are the same as on standard Chief Special. In 1957, Model 37 designation was adopted. These early alloy frame and cylinder revolvers were designed to shoot only standard velocity .38 Special cartridges. Use of high-velocity ammunition was not recommended by the factory. Note: All 1998 and later production models were rated for +P ammunition. Three engineering changes.