Colt did make some models with longer barrels, as example the 10 inch barrel Colt Camp Perry single shot built on a DA revolver frame.
Since Colt was always famous for doing just about anything a customer could pay for as a custom job, it's very possible Colt did make longer double action revolver barrels on special order.
Since these would be a special order item, there's no way to find out what may have been made up unless you own the gun and order an Archive letter for it.
Since Colt was always famous for doing just about anything a customer could pay for as a custom job, it's very possible Colt did make longer double action revolver barrels on special order.
Since these would be a special order item, there's no way to find out what may have been made up unless you own the gun and order an Archive letter for it.
