Those wall thickness you cite on the Smith's there Drew are certainly adequate. These as well as the one in question all still have the appearance of an obstruction.
We certainly have to remember that Teasdale's thoughts were written in 1900. Most steel barrels of that time were made with a very low carbon steel, on the order of a 1008 or 1010.
It did not take the industry long to begin upping the carbon content to something on the order of 1040 & soon going to alloy steels with other elements which increased the strength.
With the possible exception of those very early low carbon barrels any pressure which would bulge or burst a "Good" steel barrel would do likewise to the finest Damascus ever built.
I say this as a great admirer of Damascus, but their "Beauty" is not in their "Superior" Strength.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra