Yep! Its a nominal 12 gauge at .729". Look at the wad and card slection in the ammunition section of
TrackoftheWolf.com 's on line catalog, and read the dimensions they list for the wads and cards.
Traditionally, you would be told to buy Over Powder wads( approx. 1/8" ( .125") thick), a cushion wad( 1/2" thick), and overshot cards, approx. .010" thick. However, some find using soft, wool pre-lubed wads instead of the OP wad and cushion wads works better for their gun. Normally, FFg Goex Black Powder would be the chosen propellant, but BrownBear has been testing Fg powder and is getting tighter groups than when he uses FFg powder in his Bess.
Some members dispense with the OP wads, and cushion wads, and simply replace them with a couple of OS cards, so they only have to carry one card or wad into the field for reloading. A pea-sized ball of wax/oil is placed between a couple of the cards to lube the bore, while other simply carry a baggie with greased cleaning patches, and run a lubed patch down the barrel before each loading/reloading of the barrel. Use a patch jag on your rod, and run the patch down and then back out of the muzzle. It removes BP carbon residue on the down stroke and lubes the bore on the upstroke for the next shot. In the field, lubing the bore prevents rusting of the bore between shots, and prevents lead from rubbing off on the sides of the bore as the lead ball exits, assuming you are shooting a bare ball, or lead shot without some kind of protecting shot cup.
To determine proper ball diameter, measure the bore diameter carefully. Then find a ball that is at least .020" SMALLER in diameter than the bore. Find some heavy mattress ticking, or denim, or muslin, or linen, etc. for patching material. If you cut long strips of fabric for testing, you can place a strip over the muzzle and then pus a ball down into the barrel. If its not tight enough, just pull up on the two ends of the strip of fabric, and the ball will come back out of the barrel. If its too tight, you can go back to the fabric store and look for thinner patch material to use. Take a micrometer or caliper with you. :grin: :thumbsup: