Let me be the first to tell you that you are begging to get a bunch of people blown to Hell. Jesus, Joseph and Mary--boy, the max load for a 1-1/2" bore, proofed cannon barrel is 500 grains of CANNON POWDER for blank reports. What powder is this joker using in this cannon? Anything but Goex cannon powder is begging for suicide. Every time you go up by one F, you are essentially increasing the pressure again.
THREE FREAKING OUNCES? PLUS NEWSPAPER WADDING? Do you have the slightest comprehension what the chamber pressure in that freaking thing is approaching?
You need to get into the Cannon forum in the Muzzleloading Forum and talk to the guys that have and shoot cannons. They will suggest that your friend be institutionalized probably. Even discussing an unknown cannon that might be homemade or God only Knows what the origin is, is suicide. If you have any good judgement you will avoid all association with that, because when it blows up and kills a whole bunch of people, that way they cant sue you too.
I am setting here beside my 5/8 scale USS Constitution Carronade, which was cast by Hern Iron Works who make most of the cannons in the US at this time. I had John cast a high pressure steel liner in the barrel. The steel tubing liner is good for 15,000 psi, plus I have one bore diameter of cast iron around that. The max I use for blowing holes in an old car body at 1/4 mile is 2 ounces of cannon powder. I'm not just telling you this to hear my head rattle. You have a more than serious liability issue that you are dealing with. The School is facing a multi million dollar liability lawsuit if that sumbich goes postal. Have the cannon inspected then cut the load back to about 300 grains. It will be just as loud.
Whittington Center Life