Back in the "day"I made some when I helped Bill Large and still have one I
made in my own shop.It involved a piece of 8620,a lathe and a milling machine
and some filing.The one Curtis modified for his Alex Henry project is a fine casting
that he had to reseat due to what was an apparent error in installation.I made a
smaller version of this AH breech for a boys rifle that was stolen from my shop back
in 2008.One thing about making your own plugs is the likely chance of an internal
flaw is about zero.
Bob Roller