I'm using the Fed paper hull, 12S3 wad, 17.5 gr Clays, any primer available (Fed 209A lately and for the press test), 1 oz shot, for around 6500psi. Never had a burnthru nor does the inside of the hull look burned. Primer pockets don't get loose either. This charge of powder and shot happened to be the last skeet load I was loading with Rem plastic hulls years ago. I found the load in a manual I have which showed 7000 ish pressure. Actual testing showed it lower, but probably within the scatter.