This You Tube video follows a 1911 receiver from a raw forging through machining, fitting, assembling, test firing and shipping at the Union Switch and Signal factory in Swissvale Pennsylvania during WWII. Its a very interesting color film that even gives the acceptable accuracy that the pistol must achieve before being shipped.
Be advised: there is no audio! Semper Fi, Treetop
https://www.youtube.com/watch?v=Q7XUtgIVo7k