I merely used about 20 pound printer paper - 24pound or 28 pound would work well too, if you needed to take up a bit more windage - or perhaps thinner than 20 pound for less windage.
I liked the .006" under ball with 2 wraps of 20 pound as it engraved the rifling enough it took effort get it even with the muzzle(choked up rod with 'some' pressure). The paper jags up between the powder and the ball and effectively seals it, just as a patch would. The tighter the fit, I expect the better the accuracy - to the point of fouling screwing up being able to fire multiple shots without having to wipe.
Incidently, when I'd fired 10 shots of ctgs. from my rifle with the first being a patched round ball (11 total), I'd load 82gr. (3 drams) with a slobberly wet patch and ball and fire that off, which would effectively clean the bore allowing another 10 ctgs. to be fired before a cleaning shot (or wiping) was needed.
I haven't tried it, but 3 wraps with a normal underized smoothbore ball might be necessary. From the rifle and from the brief ctg. test in the India pattern Bess I had briefly, snug fitting ctgs. get blown out the barrel in pieces or in one piece without catching fire. Repeat - NO BURNING ctgs. If they catch fire or smolder, the combination is not sealing and needs to be increased in size, either by going to a larger ball or thicker paper wrapping.
Do not do, as I saw a while ago on TV - the "Expert" showing the bikers to bite off the paper, pour in the powder, separte the ball from the paper, drop the ball in, then ram the paper on top of the ball.
Bob has the proper loading sequence. Bite of the narrow end of the paper- stick the tapered ctg. into the muzzle - the expanded end will stop at the ball. Pull the rod out then ram it down, paper and all. Prime(or cap) and fire.
The taper should be sufficient to give you a 1/4" 'folded or glued 'end' that gets bitten off, the 'rest' of the ctg. being only large enough to hold the ball paper (folded or glued over top) and powder charge.
My .69 plug was about 3" long, tapered to almost a point. The plug for the .75 Bess was shorter due to less powder being used in it.
I would cut a sheet of paper into 4 pieces, then roll them up, gluing on the last edge with paper glue to hold them in a tube. I'd fold over the pointed end to a 1/4" wide 'butt' then glue that to the side of the tube after cutting off the excess. I would pour the measured powder charge into the tube, then drop in a ball, sprue up. No sprue balls are easier, ie; tanner moulds with sprue filed off. I would then fold the paper over the top of the ball, gluing paper to paper, not to the ball itself. Tying with string or thread can also be used.
Bruse S. and Dan P. have also used these in their rifles with excellent results. I suspect .54 or .58 is about the smallest calibre that will work wel in a rifle (& with only 2F), due to the pressure being too high in slaler calibres for the paper to maintain a seal without catching fire with heavy loads.
Nitrated ctgs. is NOT recommended by me. They only sometimes shoot accurately and only sometimes actually burn up. They give you a VERY large chance to leave burning paper in the bore. You don't want that. A friend of mine tried nitrated paper ctg. in his Sharps .54 and found unburnt ctg. tubes or pieces in the chamber or bore after almost every shot. He stopped using them on the first day of testing. He could shove a finger into the chamber area and extract a tube of scorched paper. I saw this - kinda scary to think of loading another ctg. over or on top of a burning piece of paper. So- real paper only, they thicker the better- probably.
