The original idea of the patent style breech chamber was to focus the flame and heat of the burning powder into the middle of the powder charge. In theory, this would make the powder charge burn more uniformly, and possibly faster.
It works that way with percussion ignition. It doesn't seem to work as well with flintlocks. The problem with flintlocks, is that because of the nature of the ignition system, there has to be a rather LONG flash channel from the inside of the Touch Hole, over to the back of the powder chamber, and then turn at right angles into the chamber, to ignite the powder. IF these flash channels are made Large enough, NO PROBLEMS. However, some of the makers of this style Flintlock rifle, fail to understand the need to have a flash Channel, Large enough to allow coarse Black Powder( Like 2Fg Goex) to flow down through the small( TOO SMALL) hole at the back of the powder chamber, and then over to the side of the barrel to be up next to the TH. They also don't seem to understand how easy it is for CRUD to build up in that small hole in the base of the powder chamber, and in the small flash channel, blocking any powder- even 3Fg-- from getting down into the channel and over through the channel to the TH.
Just to aggravate the situation, I have yet to find any company making these style breeches in flintlocks disclosing the DIAMETER of the powder chamber, much less the diameter of the holes in the powder chamber, or the flash channel. The Diameters seem to vary from company to company, and with the caliber sized bore of the rifle.
The problem with threading the drum into the breech plug is obvious in the pictures above: Both threaded surfaces are covered in corrosion- often as the result of Black powder residue working its ways into the threads from the powder chamber,and barrel.
At the very least, these breech plugs and drums should have their threads covered with Anti-seize compound, to help protect the metal from rust, and to insure that the threads don't gall or lock up together after some considerable use.
Anti-seize compound also seals the threads from water, as well as gases, so it prevents thread erosion, and rust from being exposed to water during the cleaning process, too. You don't ever want to see gunsmoke rising out of the back end of a breechplug, much less from around the outside of the barrel where the drum screws into the barrel! :shocked2:
Sometimes, in the foreign made guns more often than in the domestic products, you will find casting sludge, or burrs in the flash channel, that is an obstruction. You can use the next numbered sized drill bit, going through the clean- out hole in the breech of Percussion locks, or through the TH( with the liner removed) in flintlocks, to enlarge the flash channel, remove the metal obstructions, and widen the back end of that small hole in the base of the powder chamber.
Some gunsmiths remove the breechplug altogether, after removing the drum, and use an end-mill to open up the powder chamber, so that the same diameter cleaning jag that fits the rifle's bore, will also fit into the powder chamber. By driving the end mill bit deeper, the powder chamber is deepened, as well as widened, and most of the flash channel is removed. The TH liner in such flintlocks may still screw partly into the threaded portion of the breech plug, so that it "Locks" the beech plug in the barrel, but the main charge in the barrel now sets closer to the TH for sure-fire ignition and faster ignition.
Any "FIX" of these kinds of problems need to relate to the particular gun, bore diameter, compared to the barrel dimensions across the flats. As mentioned above, a .45 caliber bore in a small diameter barrel simply doesn't give you much wall thickness, into which you can thread a TH liner, or a percussion drum. What you could do to improve a .32 cal. rifle, you might not be able to do at all with a .45, or .50 cal. rifle.
A well-skilled Black Powder Gunsmith knows these things, and will make you recommendations for how to fix problems based on all his knowledge about your gun, and its limiting factors. For the home hobbyists, examining a gun in detail is the only way to begin to understand the true nature of the problems, and the limitations of the design, so that you can ask great questions here, and get very specific advice.
I would never tell anyone not to remove the breech plug of a rifle, if they have a good reason to do so. It seems to me that this is where your true EDUCATION begins, NO? :thumbsup: