In my late high school and early college days when we were loading Federal paper hulls, the trap load from the Lyman manual was 23-grains of Red Dot a nitro card & two 3/8-inch fiber wads with 1 1/8-ounce of shot. When we replaced the nitro card with the Alcan Plastic Gas Seal (PGS) we dropped the powder charge to 19- or 20-grains of Red Dot.