Lots of good suggestions here, you should try everything mentioned. The Pedersoli Scout does not have a patent breech, it uses a drum and nipple. By removing the nipple and clean out screw during gun cleaning, cleaning the drum with a pipe cleaner, should keep the ignition channel clear. This being said you mention wiping between shots is where you seem to have the problem, a couple of things. First, if you have a well maintained bore, depending on the lube being used, wiping between shots shouldn't be required, especially if you're using Pyrodex. I have no experience with Triple 7, I got a pound with a rifle some years back but gave it away. There are a number of factors which make bores foul, in my experience lube can be a big one. Second, how wet are the patches you're using to wipe the bore between shots? If there is a need to wipe between shots the cleaning patch should be lightly dampened, not wet.
I was shooting a caplock Springfield Hawken this morning. I took a fullstock. 54 Hawken, historically correct, but as an afterthought I threw in the .50 Springfield along with some Pyrodex RS. I never got around to the .54 focusing on the .50. I started with 70 grains by volume of the Pyrodex, a .490 ball, ticking patch with spit lube and a CCI magnum #11 cap. First shot perfect ignition, the next four all had delayed ignition. I switched to GOEX FFG, I forgot my FFFG, ignited by a standard CCI cap and sailed through the next 25 shot without a hitch, I did wipe the bore every 5 shots but I could have shot a longer string without doing so.
I know blackpowder can be hard to find these days but when it comes to reliable ignition nothing I've ever shot beats it.
So, with a properly cleaned and stored gun, real blackpowder propellant, wiping between shots, if necessary, with a damp not wet patch and I'd bet your problem goes away. Oh, and using a fouling scraper as part of your cleaning process might be a good idea.