I've used PB and 7624 with 1 oz. loads with no problems in guns with 2 1/2'' chambers. This morning I finished loading several hundred low-pressure loads using 2 3/4'' Remington hulls, Winchester primers, 18.5 grains of Clays, CB 4100 wads and 7/8 oz. of shot. 1200 fps at 5200 psi.