A suitable "report" is as much a function of the wads used as the powder. As I understand the physics of the process, (and I may be wrong) you need a sufficiently heavy wad to cause pressure in the burning powder, and sufficient powder so the wad approaches or exceeds the sound barrier. In my 1.25 inch diameter cannon, I found that two 1/4 inch thick leather wads made a really great boom with only 130 grains of powder. The wads are cut with a old fashioned leather punch and fit very tightly. That half inch of leather has suffiicient weight. Any less powder doesn't move the wads fast enough, or create enough pressure behind the wads. Lighter wads don't seem to work.
(Once July fourth, I accidentally took a branch out of a neighbor's tree with some wads.)