ToastedWheatie wrote:
> If Schenkl [civil war artillery shells] are one [solid] piece [of cast-iron], then maybe the smooth edge doesn't make sense?
Sorry to have to say... your theory is correct. That fragment of cast-iron is definitely not from a Schenkl shell or any other artillery shell.
Also... note that the ridge on your fragment has the form of an equilateral triangle. The ridges on Schenkl shells are shaped like either a 2x4 board or an angled sawtooth.