The question is begged... what is it that you're shooting these in?
The OP is shooting a 2 1/2" gun which I'd guess has short forcing cones and is designed for fiber wads.
Tell me you're not testing these in .741" ID Brownings.
It's remarkable that loading with traditional wads can be lost knowledge in 2 generations.
I use one piece plastic wads so don't have any experience to talk about in the fiber department except to note that BP sells an over powder gas seal (made of plastic) as a concession to the fact that available hulls today are so designed.
I did try the brass 410 shells, and the results were worse than dismal. I gave those away and chalked that up to temporary insanity.
