You know of the 4 bore we did on falling block,
with its 1 inch bore.Using turned cases and cases
made from 20mm brass. Our cases have a rim and
straight sides. A smith in the EU made a 1 inch bore
gun on a bolt action, using 20mm brass expanded
to take 1 inch bullets. His case has a shoulder to
head space on. It is called the Inch Gun by some.
It is a really nice looking gun, with great
craftsmanship.Ed