As best as I can tell, Colt didn’t start using steel until the 1860 Army revolver. There are some stories (maybe not all are reputable, but there are enough accounts to convince me that at least some are true) of early cylinders failing. A good blacksmith (should he have been so engaged) would not be able to even the odds, because he would still be working with iron. Our mild steel repros are at least better than that. By a long shot. (I’m not advocating trying to make your Italian BP repro into a .44 magnum though!)
"Colt didn’t start using steel until the 1860 Army revolver."
I too have read several times that both the Patterson and the Walker were made of wrought iron. Wrought iron is far weaker than low carbon steel because it has slag inclusions that make very effective stress risers, I don't doubt the exploding cylinders stories in the least, a Walker made today in Italy is not likely to explode unless there's a bullet lodged in the barrel or someone pours smokeless in them.
Colt used steel for barrels and cylinders starting in 1860. They used wrought iron for frames up until the smokeless era.
Howdy Again
The following is from Jerry Kuhnhausen's
The Colt Single Action Revolvers, a Shop Manual, Volumes 1 & 2. I have quoted it so many times that I typed it out and saved it as a word file. It has to do with the materials used in making the Single Action Army cartridge revolver.
"1. Early black powder model S.A.A. frames up to about s/n 96,000 (up to about mid 1883) were made of malleable iron.
2. Intermediate S.A.A. frames between approx. s/n 96,000 and 180,000 (mid 1883 to mid 1898) vary but were apparently made of transitional materials generally similar to modern low-medium carbon steels. The lowest carbon content found in intermediate s/n S.A.A. frames tested to date is approx. .0155, indicating the possibility that early formulations of 1015~1018, or higher carbon type steels may have been used in many frames of this era.
3. Although there are exceptions, frames manufactured after s/n 180,000 appear to have been made from medium range carbon steels. The lowest carbon content found in the after s/n 180,000 frames tested was approx. .0213, possibly indicating that 1020~1027 or slightly higher, carbon, or similar steels may have been used in these frames.
4.1st Generation S.A.A. cylinder material changes began to occur at about the same time that S.A.A. frames were being metallurgically updated. Cylinders prior to approx. s/n 96,000 (mid 1883) were made from materials generally resembling high grade malleable iron. Original cylinders from approx. s/n 96,000 to about 180,000 (mid 1898) were made from transitional low/medium grade carbon type steels. These cylinders and their parent frames were not factory guaranteed for smokeless powder cartridges. Cylinders after frame s/n 180,000 (mid 1898) began to be made from medium carbon type steels. Later versions of these cylinders were better and more uniformly heat treated. S.A.A. revolvers with cylinders of this final type were factory guaranteed in 1900 for standard factory load smokeless powder cartridges.
5.1st Generation 357 Magnum cylinders were made from fine grade, higher tensile strength ordnance quality gun steel. These cylinder blanks, identified by a 5 pointed star imprinted on the front, turn up on other caliber S.A.A.’s made during, and after 1935. (The 357 Magnum was introduced in 1935.)"
My point is, Colt was using Malleable Iron for cylinders and frames for the 1873 Single Action Army cartridge revolver from its inception in 1873 until mid 1883. So if Colt was using steel for cylinders and frames of their Cap & Ball revolvers, why in the world would they have reverted to iron for the SAA? I doubt it. I suspect that all the older C&B revolvers had iron frames and iron cylinders.
Yes, that is exactly why the Walker model was so prone to blowing up, the iron cylinders could not take the massive powder charges it was capable of holding.
Just a note about Malleable or Wrought Iron. It is not the same as cast iron. Cast iron is full of impurities from the casting process. Cast iron cannot be forged. Malleable iron was made by remelting pig iron and removing the impurities. Malleable iron can be forged and was an excellent candidate for forged parts such as a revolver frame. As late as 1875 Smith and Wesson was using Malleable Iron for the frames of the Schofield revolver.
But it would work OK in a frame.
