Some of the fellows on this site have noted some cap-locks having ignition trouble in events where the competitors wipe every shot as in chunk shooting. This fouling trouble seems to be from pushing the fouling down into the hole in the breech, eventually plugging the flash channel itself. With the side ignition of the flinter, if pricked, that lock would not be prone to plugging as much.
Seems to me, this is one reason why Dan built his 18 pound plank rifle as a flinter - less likely to foul the ignition with a flint gun, than a cap gun.
I don't use a breech scraper, nor does Taylor as we remove the barrels for cleaning, immersing the breech in a vessel of water and pump/flush out the fouling. My ML's are much quicker to clean than my modern guns.