What is the difference between the
Original Winchester AA and the new "High Strength" hulls?

The new Winchester target hull is a wholly new type TWO-section hull. The base and internal new piece REPLACES the smooth inner surface of the older WAA type hull creating a thick ridge in the lower portion of the hull.

The 'original' Winchester® tapered AA® hull (note that the wall of the hull thickens toward the base)

The new AA High Strength® hulls

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 (see above) that require attention.

Loading Notes:
The NEW Winchester AA® hull (refered 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, accomodating components.

At the base of the AA-HS 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 – 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. For this reason, the AA-HS requires new loading information, outlined here with specific wad recommendations.

Reloaders note: You must identify which AA hull the reloading data refers.

In BPI data:
- "Win AA" or "Win AA-old" refers the the original, tapered AA hull
- "Win AA-HS" refers to the new, three piece, High Strength hull

AA and AA High Strength are Trademarks of Winchester-Olin.