Muleman you need nitrate paper to make your paper cartridges. You can order the paper or you can make your own. I recommend you slug your bore, even though it is 54 cal. Dixie-Track of the Wolf-even Midway and several others have various molds,some primitive and some a little more modern. If you have some of the bullets you can shoot your rifle with out the paper by putting in the bullet and putting the powder on top till full-close the breech as if you were slicing off the paper catridge-then cap and fire. The paper cartridge is more for your convience than it is necessary. If you are going to build the paper cartridges you should order a kit for building them or do some reading to learn how to make the template to cut the proper size paper, the correct size of dowel rod to wrap the paper around, and the glue to hold the bullet and paper together. I will recommend you wear shooting glasses because the one that I fire does not seal completly. I get some little burning sensations across the forehead. The one I shoot is a replica, but I am amazed at the distance this thing will shoot compared to a muzzle loader with the same powder charge. Hope this helps some.
I shoot a Garrett Sharps replica, made by Palmetto. They are as faithful a repro as is out there but they too have an issue with blow-by. We have a part time gun smith that does an incredible job manufacturing a new breech block that eliminates this. I purchase cardboard tubes from him that we seal the base by gluing curler paper to it, I use a .54 cal cast ringtail bullet that also gets glued to the tube. He has also fixed my trigger pull to 4 lbs, minimum for our shooting is 3 lbs., pull was 10 lbs.
If you are interested I can put you in touch.
I picked up an IAB 1858 (I think) Sporting breech loader. I bought the paper cartridge kit from Dixie and wound up making my own dowell for making the paper cartridge case. What I did was measure the chamber with a bullet (Dixie) just seated against the barrel in the chamber so that the over all length of the finished cartridge was about 1/16th inch long. That way when I closed the the breech the back end of the cartridge would be sheared off. I think my final charge was about 55 grains (volume not weight). My IAB does not have the floating chamber but does have a floating pressure plate that seals really well.