Don. The vent, or touch hole should be located above a line draw across the top of the pan, where it joins the barrel. Some are a little lower, where that line splits the the vent hole, half above, and half below the line. If your vent is lower than that, you have to not only use less priming powder, but you will always have to bank the prime away from the touch hole. If you block the touch hole, the powder had to burn down before the heat can enter the barrel and ignite your main charge. That leads to a delay in ignition, a so-called hang fire.
once you have the vent located, and know where to put the prime, then, and only then can you answer " How much priming powder?" If the vent is substantially above the line, or top edge of the pan, you may do well to fill the pan. I recommend grinding the pan broader or wider, than it comes from the factory, using a small grinding tool in a hand drill, or a dremel tool. A wider pan allows a bigger target for the sparks to hit so you ignite the prime quickly.
Next, you want to clear a hole into the main charge by using a vent pick to stick through that vent or touch hole, and push all the way to the other side of the chamber. This makes a place for the flame and heat of the priming charge to ignite more than one granule of powder. In a flint lock, you ignite the charge one granule at a time. It speeds the ignition of the entire charge if you can ignite more than one granule in the chamber.
In contrast, a percussion cap gun injects a hot flame into the powder charge, burning a pushing its way through the powder to ignite it all very quickly. With a percussion gun, you pack the powder down hard, using drop tubes to load the gun, and pushing down on the ramrod when you load the PRB.
In a flintlock, test show conclusively, that the best accuracy is going to be obtain by loading the PRB to just touch the powder in the chamber, without any compacting at all. This leaves the powder loose in the chamber, puts more air around each granule of powder in the chamber, and thereby speeds ignition of the charge uniformly. The test show the same charge of the same powder loaded in a flint lock this way, as opposed to being compacted in a percussion gun will produce slightly lower velocities in the flintlock, than in the percussion gun. This difference can be easily compensated for by using slightly more powder in the flintlock. While the percussion system is fairly closed, that flintlock still has that vent at the back of the chamber, bleeding off gases, and reducing velocity even as the ball is moving forward down the barrel. The size of the touch hole actually has a minor role in determining how much velocity is lost when comparing equal charges of the same powder, one in a flintlock, and the other in a percussion gun.
You might want to read my article at: [url]
www.chuckhawks.com/flintlocks.htm.[/url]
It might help you understand how that flint lock works, and how you can iprove it yourself. Paul
