If you hang a round this board very long, you will quickly find Cannon Mania is seldom mentioned. You will not find them listed on our Cannon resource list. They have a very bad reputation with the members of this board and their references are less than creditable or safe. There are membrs of this board who are still owed money by Cannon mania. If you must have the details, do a search of the forum. You will find them.
That Cannon Manai load chart is way off. FFG doesn't go in cannons. Some loads are overloads. Some are underloads. Then in the fine print, you find the loads listed are blanks loads. That should be in Big bold print
If you want good safe and sane load recommendation from a creditable source go to the sticky at the top of this forum and look for our post safe loads and Cannon plans. In that post you will find a load chart for guns under 2 inch from Matt Switlik's book "The More Complete Cannoneer." Switlik is an acknowledged expert in the field of Muzzleloading Cannons. Use those loads.
Cannon-mania is the last palce to go to seek advice.