Was shooting pitted laminated twist 10ga with 10-12ga chamber reducer yesterday. Used 7625 with 1oz and 800x with 1 1/16oz. Clays with 7/8oz wouldn't seal in the very over bored 12 (poor pattern)I think 7625 and 800x hold pressure longer to seal wad in very over bored 12. Black also holds pressure longer (see chart C above). I use real FF or F with 1 1/8 when hunting. PSI in load data is only one thing to look at. Also if you haven't read Sherman Bell's "Finding Out For Myself" articles in the Double Gun Journal, they are very interesting, concerning shooting damascus and twist barrels.
