I received a great amount of vintage reloading equipment . Some of it is molds. This one particular mold is from the Ideal company. Not sure what year, but vintage for sure. It is a cast iron block that has been drilled our & re-poured with a brass inner. Then chambered. Attachment 307731Attachment 307732Attachment 307733Attachment 307734Best I can tell it is a 41 cal. I guess for the 41 Colt. An help you gurus can provide would be appreciated.Attachment 307735