A well made flintlock will often fire without powder in the pan.
First time I’d ever heard of it. Guess the good news is that I have a “well-made flintlock”.
Black Powder can be very volatile, or it can, if it has gotten wet over the years, completely deteriorated. Need I say DON'T LOOK DOWN THE BARREL OF AN OLD GUN TO TRY AND SEE WHAT'S IN IT?
I got an old screw type bullet puller and, sure enough, there was an old lead ball, a greasy patch, and a powder charge.
I could have tried to unload the gun by firing it, but I had no guarantee that who ever had loaded it did not load it with a charge of smokeless powder which could destroy the gun and possibly injure me.
IT'S NOT A GOOD IDEA TO UNLOAD AN OLD PERCUSSION OR FLINTLOCK GUN BY FIRING IT IF YOU DID NOT LOAD YOURSELF. . . You can't know what it was loaded with.