I never ever did get really nice crimps with Federal papers, even when I was loading them by hand with a Lee Loader. something about the way they are made, they just never crimped well. Not enough wax in the cardboard, something? Super-X, Remington, and Alcan all crimped better for some reason. I suspect you may have the wrong wad, not enough wad pressure, and with papers it is very important to get it right, the crimps will open up and get holes in the centers and even fray a little bit. There is a real good reason that reloading shotgun shells really took off after the advent of plastic hulls! One piece wads helped considerably too!
BP