As I interpret W Greener in "The Gun, 1834" he did show Wire Twist being slightly stronger than Stub Twist @ a tensile strength of 79K+ psi for the wire & 76K+ for the stub. It did seem to me though he much preferred the stub over the wire at that point in time, thinking the steel & iron had a much better blend & less apt to break in the weld from a sidewise blow.
He also warned that many wire twist bbls were sold as stub twist ones. Even at that point he was bemoaning the fact that the stubs were getting ever harder to accquire as many of the horse nails were going to a cast product which was totally unsuited for use in gun bbls.
The very steep inclination of the pattern in question looks much like what he described at that time as "Two-Penny Iron" of which he had nothing good to say, it having a tensile of only some 39K psi.
PS; Whether any of this still held true by the time these bbls were made I have no idea. This was all taken from the 1834 work.
