Mine came from Enco, too. Seem to work on mild steel just fine, although
it is tricky to get them lined up square so that they imprint evenly.
To align letters on a bbl well, you need some sort of a jig to lay the flat
side of the punch against (parallel to the bore axis) to keep letters/numbers
from being angled right and left, and displaced up and down. Clamped
into a hardwood alignment jig would be good enough, I think.
Maybe C-clamp or vise grip several together to get them lined up with
each other, then hit with a hammer spanning all of them.....
I am not happy with freehand results, never did anything that I cared
much about getting nice like a bbl. Have thought about it a bit, but never
done it.
Bill