The Winchester AA hull (referred to as High Strength or “HS” by Winchester) is a three-piece Reifenhauser-type design. It consists of a brass head, an inner tapered base resembling a plastic cup and a straight length of extruded plastic tubing.

AA Architecture

The AA-HS averages 2.7″ in overall length. The distance from the mouth to the top edge of the inner-base cup is 1.9″. This allows for a maximum wad length of 1.4″ (with a 0.5″ crimp depth) with a bit of wad compression. (Note: Wad compression does not consist of ramming the wad into the hull with thirty pounds (or more) pressure. Minor wad pressure of no more than ten pounds should be required.)

Winchester advises that the original Win AA and the new Win AA-HS hulls are interchangeable. In the general sense of speed and pressure this may be true. However, there are some fit and finish concerns that require attention and different, accommodating components. At the base of the AAHS is a .020″ thick rim edge where the inner-base cup meets the plastic tube. The ridge catches the gas seal of many types of wads, thus stopping the wad from progressing deeper into the hull. This prevents the gas seal from seating directly on the powder, which is required for proper load combustion.