Help me understand the anatomy of my barrel; Stepped design inside?

[Numlok]

So I've shot my Traditions percussion Kentucky Rifle a few times now. Cleaned it diligently after shooting. But me, being the sort that likes to take things apart, decided to take the screw out of the drum (Even though I've seen people advise against it. I really can't help myself.). I was curious how far the barrel went back past the drum, so I stuck a mop down there, and to my surprise, I didn't see it through the hole. Just like when I was cleaning it before, it felt like it was bottomed out. Did the same thing with a cleaning patch on a jag, and again, didn't see it through the drum hole even though it felt like it was solidly bottomed out.

So, the conclusion I'm coming to is that there's a narrower portion at the bottom of the barrel. If that's the case, how large is that chamber? Small enough for powder to completely fill when loaded? Or should I be worried about an air gap in there if I ever try a lighter load (Haven't gone under 50gr so far. Not really intending to, but would be good information to have.).

Past that, it's making me realize that I wasn't as diligent as I had assumed with my cleaning, since I wasn't getting down into that chamber. What's the best way to clean all the way down in there? And the best way to remove any moisture after cleaning? I'm worried I've left all kinds of wet gunk down in there, just corroding the heck out of that chamber.

I always assumed that the rifle would have a straight rifled cylinder all the way down to the plug, so I'm a little bit surprised to find out otherwise. Is this a quirk of the Traditions Kentucky Rifle? Or is this common in other rifles as well?

 

[TreeMan]

Search Patent breach on this site. That’ll answer your questions.

 

[longcruise]

The breech plug has a hole in the center about the same size as the threads on the drum. The threaded potion of the drum screws as far as the hole in the breech plug. Pictures of the system show the drum screwed in beyond the far side of the hole in the breech plug with a hole through the side of the drum threads. The several that I've had apart weren't like the pictures.

I've seen pictures of the same system in a disassembled state from an 18th century German rifle.

 

[longcruise]

Here's a picture of a plug and drum from a new barrel.

 

[Numlok]

Search Patent breach on this site. That’ll answer your questions.

Ahh, thanks! I figured there would be a name for it! Definitely helps my search.
So from my quick bit of research, it seems like I should be able to get down in there with a .30 mop or patch holder to get that portion cleaned out. Or maybe I'm just worrying too much. Watched all sorts of videos about cleaning muzzle loaders, and never heard anyone talk about this!

 

[Numlok]

Here's a picture of a plug and drum from a new barrel.

View attachment 283383

Oh that's helpful! Awesome to be able to visualize it! If you hadn't posted this, I probably would have gotten a little too curious and torn my rifle down to get a good look at the system Thanks!!!

 

[necchi]

https://www.muzzleloadingforum.com/threads/cva-drum-leak.70716/post-876018The photo will give you an idea of how they where made, with specific information about the technique of "indexing" and why.

Your right in your concern of moisture accumulation. There are several methods. And if you search you will find them. This forum is an encyclopedia.
I use tepid water and mild soap for cleaning ("clean" should be commonly understood).
After using dry patches to remove all water. I use denatured alcohol as a rinse.
It's a simple matter to plug the nipple/port with one hand and pour a 1/2oz in the muzzle, then slosh back-n-forth.
The alcohol readily mixes with water, then pour off and let the alcohol evaporate.
Follow with your desired preservative, (that's another topic)

 

[Numlok]

https://www.muzzleloadingforum.com/threads/cva-drum-leak.70716/post-876018The photo will give you an idea of how they where made, with specific information about the technique of "indexing" and why.

Your right in your concern of moisture accumulation. There are several methods. And if you search you will find them. This forum is an encyclopedia.
I use tepid water and mild soap for cleaning ("clean" should be commonly understood).
After using dry patches to remove all water. I use denatured alcohol as a rinse.
It's a simple matter to plug the nipple/port with one hand and pour a 1/2oz in the muzzle, then slosh back-n-forth.
The alcohol readily mixes with water, then pour off and let the alcohol evaporate.
Follow with your desired preservative, (that's another topic)

Oh that's a great photo! Another awesome visualization! That portion is definitely smaller than I was imagining. But yeah, still concerning for sure.

The denatured alcohol is a good call. That stuff flashes off nicely. I'd imagine it makes a good solvent for anything that may have been left behind as well!

And yeah, this forum is a great encyclopedia. With the caveat that you have to know the right keywords to search for. Still working on learning all of those This thread has been enlightening so far though!