I can see no reason to load that much powder or shot to shoot clay targets. That first device on the forestock in front of the trigger guard is not clear in the picture, but if I recall my history correctly, these guns were often fitted with a swivel, like an oarpin, which fit into an oarlock on the railing of sailing vessels, so the rifle could be steadied and fired like a swivel cannon. Being a rifle, it could also be carried to other parts of the ship to allow it to be aimed at an enemy or pirate ship approaching from a different direction. Large shot, as well as old nuts, and bits of nails were loaded into the barrel to fire and clear sharp shooters from the masts and rigging of the approaching ship, as well as to sweep the decks with a murderous blast of shot. Like most crooks, Pirates were in the business to make a quick buck, not get badly wounded or killed. This kind of gun often deterred an attack and allowed the ship to escape with its crew and cargo in tact.
Save your shoulder, and the price of powder and shot. A load of 2 oz. of shot, and 3 drams of powder should be a light, but effective load for shooting clay targets. The pictures you took here should satisfy the testosterone needs of any of your friends, unless they insist on shooting the gun with powder and shot they provide! You may even be able to reduce that charge of shot down to 1 1/4- 1 1/2 oz. After all, the targets are going to be broken inside 25 yds, for the most part, and just how much shot do you need to break a clay target at those distances? With that huge bore diameter, your shot column will be very short, meaning the shot will arrive at the target in a shorter " string " than what you get shooting a 20 or 12 gauge.
