12S0 wad. 1oz magnum shot, 18.2-18.5 grs of Red Dot or Promo, Federal 209A primer. Clocks a little over 1200 fps and works like a charm. I would use a primer like the RIO G600 on the second loading and then toss the hull. The larger diameter of the Rio primer will help seal the case head, since they have a tendency to leak around the primer after a few loadings.
Estate and wally world cases.
I load 17.2 700x, Noble 209 primer or Winchester, Downrange DRXL-1 with 7/8 oz 8.5 shot for 16 yds and first shot in doubles. I also use the same recipe with Rem target 12 or Downrange clone and 1 0z #8 shot. I had to go to almost no wad pressure to get the crimps right, but Downrange says you do not need any pressure on their wad. Go their website for more details. Dump the shells on the second reload. Primer pockets do not last long. Lance Howard