I have a Jim Chamber's roundface flintlock on one of my guns. It's the plain-jane model, not the fancy English one with the snazzy water-proof pan.
I am pleased with it's performance J.C. makes a fine lock. And even though it's the lesser of the two locks, it's durn-near water proof. Just smear a tad o' grease under the frizzen and such and it seems to work in all weather.
The only drawback maybe is the speed - granted I use 2f as a prime, which should indicate to you that this is very minor to me.
Anyway, part of the secret to fast lock time is to have the torch-hole above the level of the pan powder. That way the fire-ball can go into the hole at the speed of light rather than trying to burn it's way down to the hole like a fuse.
I assume Chambers knows this. But on the bottom of the pan cover there is a little notch bevelled into the cover right about where the torch-hole would be.
It's almost as if it was intended to allow the pan powder to fill in there creating a fuse to the torch-hole. This seems counterproductive, something one wouldn't expect from a Chamber's lock.
The other possibility is that this is to improve water-proofness. Does anyone know for a fact that this is the intent? If it is, it is possitively ingenious!
Here's how I think it might work. Since the touch hole is supposed to be above the level of the pan, it would naturally be covered by the pan cover when the frizzen is placed down.
In good weather, this would not have an affect on the ignition. However, during rainy weather, access to the torch-hole would be through the very thin space between the pan cover and the side of the barrel. Capillary action would wick the water into this minute crevice and then into the powder charge through the torch-hole.
The way to stop capillary action is to open up the gap on the other side or expose the torch-hole to the open space underneath the pan cover. So the water is held between the pan cover and the barrel flat but can't get at the torch-hole because the gap suddenly opens up so big - right before the water gets into the torch-hole.
I'm having a difficult time describing this but: imagine lifting a straw out of a glass of water. Almost all the water drains out, but there's always that little drop left at the bottom of the tube. That's because it is held there by capillary force - or the water has a tendency to "stick" to surfaces. The surface area inside the straw is enough to hold a small drop of water.
That drop of water will remain stuck in the straw refusing to fall into the open atmosphere. Then when you touch it, you provide a surface for the water to cling on to and the water drop wicks out of the straw onto your finger.
Well imagine drilling a tiny hole in the side of the straw right at the bottom. The water drop will remain in place just as before. Except now if something touches that hole the water will wick out through the hole.
Imagine the straw is the gap between the pan cover and the barrel flat. Imagine the hole in the side of the straw is the torch-hole. Imagine that your finger touching the hole in the side is the powder charge!
Now if the torch-hole is not drilled into the side of the straw, but is below the bottom opening, it will be safe.
I haven't tested this. I've always put a bead of grease to seal that gap between pan cover and barrel. However, I don't know how effective that grease is - I know I've had the grease fail on my other flintlock, but it hasn't yet on the Chambers lock.
If this is confusing anyone let me know and I'll try another stab at explaining it - maybe post a rough sketch.
