So a couple days ago, I found a flat of loose shells that I had (stupidly) set in my garage last fall and forgot about. When I opened it up, I saw a bunch of rust. Dang it. So I went through and wiped them all down with a rag and WD40. What I found kinda surprised me. The pile on the left are perfect, no corrosion. In the middle, will still shoot but have some corrosion. On the right, are going in the garbage. The Federal Premiums (red box) had little to no corrosion for the most part. The Estates did ok, and the Kents were almost all corroded really bad.
For the second part of my test, I tore into the shells to check out the powder, wads and pellet uniformity. The wads were all different, with the Feds and Kents both having a one-piece wad and the Estates having a 2 piece wad. Powder was nice and dry in all three. However, the pellets in the Estates were absolutely abysmal. Every single one was deformed and had some kind of flaw. Slag, dimples, ovality, etc etc. See for yourself.