Lonesomebob: YOu might try a package load of 1/4 powder and 3/4 flour to get the " bang " you want. I would think that about 150-180 grains of powder would be sufficient, with the flour added to make the kind of noise you want. Be careful about using paper. It will ignite, and on a dry day, you can start a grass fire. Even with wet paper, you can have glowing embers on the ground from the edges catching on fire. I was part of a cannnon crew years ago, and we make our loads up in aluminum foil, so we didn't have to worry about static electricity setting off the charge. The black powder was positioned at the back end of the cylinger( Wrap the foil around the ramrod head to create a cylinder, closed at one end. Then remove it from the rammer, and upend it to put the powder in. Powder, then flour, then twist the top closed, and fold the top over. We would use a brass rod filed to a point to run down the vent to pierce the aluminum foil charge. Then use cannon fuse, or 4F powder for prime and touch her off. The flour gave enough mass to move that we got the compression needed to make the same loud boom that a full pound of powder made firing out of our light 6 pound field piece. Oh, the cannon was a casting from South Bend Replicas, with a 1/4 inch steel liner in it, weighing 550 lbs. for the barrel alone! While the liner was able to hold the pressure of the charge by itself, I would not have wanted to fire those kinds of charges out of that liner by itself many times. That is asking for trouble. You may get away with using your cannon as is, provided you reduce the powder charge to something that will not create the kind of pressures you have already used the cannon to test. It took us a lot of experimenting to find this combination of powder and flour to use for blanks to please the crowd, so I hope it helps you out. The flour burns up, so don't be expecting people to be covered with flour after the cannon fires, like some slapstick comedy movie with Laurel and Hardy, or the Marx brothers.