I suspect that you want to shoot more than 30 times without going through a major clean up at the range. Let us take a look at the new CVA style breech to see how the dirty breech could be the cause of the failure to fire. We can also see how a vent pick isn't likely to get an open channel to the powder charge.
View attachment 292970
We can see that the hole in the breech plug leading into the powder chamber can become bridged with fouling. A wipe with a 22 or 30 caliber brush with a cleaning patch wrap dampened with rubbing alcohol will clear the fouling so shooting can continue.
What you didn't say is if you are wiping the bore between shots or occasionally during the shooting session. You have a couple of choices to deal with fouling that can bridge the opening in the breech plug.
As has been mentioned earlier, a cleaning that flushes out the breech will do it.
You can also select a smaller jag than the bore sized jag so a dampened patch will slide over the fouling as the rod is inserted while bunching up to pull fouling out of the bore.
You can wipe the chambered breech with the subcaliber patch to clean out the chambered breech.
You can send a blast of high pressure CO2 from a ball discharger through the touch hole to blow out the fouling bridge.
You can do the never wipe method by loading the powder the patch the ball with a wet patch to wipe the bore as you load.
There's also the load the powder, then a lubricated bore sized wad. Wipe the bore with a damp patch then the patched ball. Really this may be too many steps to shoot the next round.
There's probably several more methods to prevent fouling from making a bridge or dam that will block the flame getting from the touch hole to the powder.