Older AA style 16’s

[Quigley97]

The newer AA hulls are two piece hulls. The base wad is pressed in the bottom of the hull and the the metal is crimped on the bottom. I have measured the gray AA's after numerous reloads and the inside length grows account of the base wad compressing, thus the shells crimp differently after loaded three or four times.

[Mark Garrett]

The 16ga Compression formed hulls are completely smooth on the outside no ribs at all. They don't the have a separate base wad , all one piece . If you shine a light on the inside you see can the difference and they are tapered . Most not all had brass heads , some of the later ones where steel .