The Hercules was made by Iver Johnson for Montgumery Wards. Production probably started just before 1920 and went until the early 1940s. The "Hercules" name was dropped around 1936 and was known as the Iver Johnson Hammerless. But a special run of Hercules guns were run in the 1930s under the Western Field Model 53 name. Does yours actually have the name "Hercules" on the gun? If so, it was probably last made in 1936.