Replacement TC style breech plug cleanout screw

The plug in question is from Track of the Wolf. While not intended as a cleanout screw, the hole opposite the snail came supplied with a hex head set screw. I wonder how far the threads go up in there and if a pan head type screw and accompanying counter bore might be a better choice.

Has anybody ever seen one of these plugs sectioned?

Mine is currently installed on my new barrel and I'll have to make a wrench to remove the plug if I want a better look at what the flash channel looks like inside. I was preparing to file the plug before browning and so I pulled the screw out. That is when I got to wondering about how far the threads go in and what the screw seals against inside the breech. Anybody know?

Thanks,
Ben

In my experiance the hex allen is a better bet. If neglected even a little that screw will seize in there and the allen has a better bite to get it out.
I use the bucket/pump action method for cleaning and long ago gave up worrying about that screw, it's hole, and any advantage or differance while cleaning.
Too my knowledge it doesn't Seal or Seat against anything, the hole is tapped all the way through to the flash channel. The screw just plugs the hole and ends wherever it ends. But there's stuff I don't know.

Now in the CVA/Traditions type drum breech it's a different story

I'm not familiar with that exact plug, but I suspect it's like a breechplug blank I used once. If you're saying that the cleanout screw is on the opposite side of the nipple, then the flash hole for the nipple was drilled from the opposite side, to the bottom of the nipple hole. The flash hole should be the minor diameter of the thread of the cleanout screw (8/32 I assume). The left side of the breechplug is then tapped and plugged with the cleanout screw, which should end flush with the inside of the breech chamber.

On the blank I worked on, I just plugged the left side with a screw, then filed it off flush and browned it, never to be taken out again. There's really no need to ever remove that cleanout screw, but if you think you may want to in the future, that hex head is your best bet. I would just leave it as is and forget about it. Bill