Tool steel has also been used. I also saw stainless mentioned once, but I'm not sure what application though.I would have to think that stainless would need to be run in a cylinder with some sort of a coating.
The most common materials are are either gray cast iron, or nodular iron with metallized molybdenum on the face. That is the "chrome moly" that you were refering to. Also, chromium faced nodular iron is used in some applications. '85 Mercury Capri
Mild 351 Cleveland powered
6.78 @98 mph 1/8 mile. 1.45 60 ft.
