With proper wadding, you can obtain 8" groups from a cylinder 12 bore double at 100 yards with BP loads - mine did. Several friends over on nitroexpress.com are working with BP round ball loads for their old (and new) double guns, 20 through 10 bore. Some are having better success than others - it's all in the wads & how they're used. I used .684" WW balls in .725" bored, 24" tubes. The heavier the load, the better they shot-- to 7 drams. That was a kicker in a 7 pound double. Taylor said it spun me around like a weather cock. It did split the wrist, but the repair held. Nice, powerful load. No reason the same type of loading wouldn't work in a cylinder or jug'd musket or fowler. What is needed, is a wad that will centre the ball in the bore - the rest is in load development. The original light 12 bore load was 110gr. fine powder. FUN, FUN, FUN.