Make your own wads with 1/8" sheet felt from Durofelt of Little Rock, Arkansas. Find the site on the net ... I'm too lazy to look it up.
Use a .45 ACP or .45 Long Colt case with a sharpened mouth to cut the wads. Before doing so, remove the primer from the case and drill out the primer pocket. A short length of stiff wire inserted from the rear will push out the cut wads.
With 100% wool felt from Durofelt, and a cartridge case, you'll be able to make wads for less than a penny each.
Use the end of a length of log or 4X4 to cut the wads against. The cutter will sink into the grain, making a clean cut. Cutting against the grain, along the side of a 4X4, requires significantly more pressure and will break off splinters into the wad.
Lubricate the wad with a mix of Crisco or lard, and beeswax. Or use the commercially available SPG or Lyman Black Powder Gold lubricants, designed specifically for black powder.
Or you can use the homemade lubricant, based on a 19th century factory bullet lubricant, that I altered somewhat years ago. It was soon named for me: Gatofeo Bullet Lubricant.
1 part canning paraffin
1 part mutton tallow (sold by Dixie Gun Works)
1/2 part beeswax
All measurements are by weight, not volume.
Search the net for Gatofeo Bullet Lubricant and you'll find more explicit instructions.
This lubricant is superb for black powder patches, revolver wads, shotgun wads and lead bullets.
As to your problem ...
Sounds like a nipple problem, to be sure. Try squeezing the caps into an elliptical to make them cling to the nipple. They may be too loose, despite the cap you had to cut off -- you don't say if it was before or after an attempted firing that it became stuck. If after, then the hammer may have crushed the cap against the nipple.
I'm not one of those who believes that multiple ignitions originate from the front of the cylinder. I believe it starts at the rear, when a loose cap is dislodged by recoil, or drops off unnoticed.
Back in the 1970s, with a cheap, brass-framed 1851 Navy in the unauthentic .44 caliber, I experienced three separate incidents of multiple ignition. The last incident damaged the gun beyond repair.
This was with DuPont FFFG black powder, a .451 ball, no felt wad, Crisco over the ball and Remington caps. In those days, I hadn't yet learned to pinch caps into an oval, or to use a lubricanted felt wad under the ball instead of grease over it.
I recall that the revolver's chambers positively ran like a river in melted Crisco with the first shot. I just don't see how any spark could get past that, and the ball that left a ring when seated.
Sounds like you have some cap and nipple dimensions to work upon.
"And lo, did I see an ugly cat. Smoke. Brimstone. Holes in parchment. And this ugly cat was much amused." --- The Prophesies of Gatodamus (1503 - 1566)