I know this has probably been posted before but the search won't let me use things like "AA" (says it is too short) so I get a zillion hits both here and on the reloading forum. I'll try here first. I am finally running out of old AA shells to load. I had been picking up the "new" AA hulls and have a bunch to reload. But when I look at them, they seem to have an extra layer part way up the inside of the hull. I can see it looking through a strong light and can feel it if I run my little finger down there. Was this an improvement, something to make the hull stronger, or a cheaper way of doing things? Does it require anything different from loading the old AAs?