I'm told that Winchester no longer makes the WAA12F1 wad. I'm at the end of my stash, and need a replacement. Minor adjustments in the final crimp die will facilitate a suitable crimp. PR Inc. does not sort out these variable length hulls as it would not be cost effective for the end user. All manufacturer's shotgun hulls differ in design, consequently cannot be interchanged as is the situation with powder, primers and wads.
Federal hulls are of three designs.
One with a paper basewad and two with different plastic basewads. All designs are straight walled. Winchester has two hull designs. One Compression formed and one Polyformed. Compression formed is a one piece tapered design whereas Polyformed is a straight wall design.