I was thinking along the lines of decarbonized using a wood or charcoal fire...instead of coal or peat or old phone books or whatever else they used to burn back then.
So off I go surfing. The e-gunparts forum has two answers to a question about decarbonizing. The first is that the manufacturer uses it to mean what they like. The second is:
http://www.muzzleblasts.com/vol4no3/...s/mbo43-3.html "Basically, that is homogenous wrought iron that has had excess carbon burned out. Link above is a good article on making of gun metal in the 1800's at the Remington forge. I would check with Remington before firing this with ANYTHING- schrapnel gets SO personal. Good luck- and please let us all know what you find."
John