CZ

Pre 1900 steel selection was pretty limited, 1018 may be at the bottom of the barrel today, but pre-1900 it was about as good as it got. Spring steels such as 1095 were pretty expensive to make.
It wasnt until the railroad, aviation and automotive industries forced the development of better and stronger steels. I believe it was General Motors which first developed SAE 4140 for use in car axles.
Today we all know the 41xx series steels as the most popular steel for barrels.

Mike Hunter
www.mikehunterrestorations.com