I am suspecting that you don't flush the oil in the powder chamber, and the flash channel in the rear( breech) of your gun before loading that first charge of FFg powder, using alcohol.
The Sequence you describe, where the first shot fires fast( as fast as you know), then each succeeding shot gets slower and slower( hang-fires) until the gun won't shoot at all is an indication that these small channels are building up crud because you left oil in them before loading that first charge of powder. Then, as you fire the gun, TARS- yeah- just like the black gunk left behind from smoking tobacco---- build up until powder can no longer flow through the small hole in the powder chamber and over to the Touch Hole.
First, change your cleaning procedure, and flush that barrel with alcohol to dissolve the oils and congealed grease that collects there.
Second, change your storage habits. Store that gun MUZZLE DOWN, so that any extra oil you leave in the bore will go out the muzzle instead of back into the flash channel. Put some paper towels, or folded newspaper under the muzzle to soak up the oil and keep SWMBO happy! :shocked2: :wink:
Third, Consider changing your powder choice to FFFg Goex, as the smaller sized 3Fg powder more easily gets thru and across the flash channel when you push air in front of the PRB as its loaded down on top of the powder.
Fourth, Close the frizzen to keep powder from being blown out the TH, and load the PRB down slowly, using a hand-over-hand technique on the rod, with neither hand more than 8" above the other.
Fifth, Do clean that pan and frizzen off of residue between shots- its the first part of my gun I clean after a shot is fired--- as the residue is hydroscopic- meaning it absorbs moisture from the air.
Sixth: Mark you ramrod, and range rod, and always load to the mark, carefully. When you run that first cleaning patch down the barrel after a shot, don't run it all the way to the bottom of the bore( and in front of that narrow powder chamber). Instead, stop 1" above that spot( You did mark your rod, didn't you?), and pull the crud out. Then using a new dampened patch, run it down to the breech as far as it will go. Let it sit there a moment so that the moisture in the patch will dissolve the crud back there, and the soft fabric will soak up the crud for removal. This is always far better than shoving the crud down into that powder chamber.
Now, use a clean dry cleaning patch to go down and dry that barrel. If that patch comes out slick and gooey with crud, use a second and even a third dry patch in the bore. How much crud and moisture there can be in a bore varies with the temperature and relative humidity on a given day, or given hour. Read those patches as they come out of your barrel: they will tell you what you need to know and do.
Some shooters keep a separate rod at the range with them that ha a smaller diameter brush, or cleaning jag to get down into that powder chamber. Others simply have the jags along, and change them if they think the chamber needs cleaning.
By flushing the powder chamber and flash channel with alcohol at the outset, and then NOT shoving crud down into the chamber from the bore, you can usually shoot all day without any clogging of the chamber that requires you to clean it. :surrender: :thumbsup:
Don't beat yourself up about all this. This is part of the "Learning curve" of shooting flint locks. The Lyman designed gun, with the powder chamber and long flash channel just adds some more problems.
You want powder visible next to the TH, but you don't want it plugging the entrance in case of moisture wetting that powder. Use a vent pick, but don't remove all the powder you can see. Hopefully, you have an inside coned TH- that allows powder to rest above and below the hole itself to catch the heat from your burning priming powder.
Some THs work best if opened up from what comes from the factory. Use drill bits to determine what the current hole size is on your TH. Usually its smaller than 1/16"(.0625") You can go up to about .0700"(#50 drill bit) before any FFFg Goex powder begins to blow out the TH. :hmm: :hatsoff: