I remove the barrel from my old rifles to clean them to protect the wood.
At the range, after I load the gun, before I cap it, I turn it over and give it a spank to set the powder as low as it can go.
If it still doesn't shoot, I remove the nipple and pour some powder into the flashhole, replace the nipple and it should fire.
I use Goex FFG. FFFG is too hot. Pryodex is tough to ignite (in my old guns at least).