Originally Posted By: GregSY
A breakthrough occurred in the 1980's when some gunsmith ran across the Flex Hone? How is 'running across' a tool that has been around for ages a breakthrough?


Flex hones were invented in the '60s for automotive use and began expanding into other industrial / manufacturing applications during the '70s...then grit sets in gauge sizes on 34" shafts for shotgun bores started becoming available around 1980.

http://cr4.globalspec.com/blogentry/8261/Have-You-Tried-Flexible-Honing