I just got a lyman 5th edition loading manual and have a question concerning its use. Are the winchester AA hulls what they refer to as Winchester HS or Compression formed plastic cases ? Thanks.

Jim, AA hulls can be the new HS version or the old Compression formed type. If you have some HS's you can see a separate base wad on that model. The old compression formed AA's are a unibody design (no separate base wad). BTW there were compression formed hulls that were not AA's and were designated for hunting uses.

In the reloading sections, for instance in those under the Lead Shot blue tab, it will diferentiate between HS and compression formed.