Kevin,
The shiny spot on the flat was caused by me when I put a flint in the gun without lining it up correctly. The flint edge struck the barrel flat, causing the shiny spot. That was a hard lesson to learn, but I won't do it again.
I will take your advice and make sure I don't over tighten the lock bolts.
I use the round toothpick when I clean, but I have not tried to shoot water out of the touch hole as you mentioned. I will certainly give that a try. I was trying to keep water off the wood, but I can wipe it down when I am finished.
I am still trying to dial in the load for this rifle. I think it has round bottom grooves, but the coning is so deep, I am not really sure. I was using a .530 ball with pillow ticking patch, but I was getting cut patches and burn through. I was testing .535 balls when I had so many ignition problems I gave up and shot another rifle instead.
Thanks to all for your suggestions. I think at this point I will clean the rifle again, using all the techniques described, then test it again and let you know how it works.
I do think at this point the problem may be narrowed down to maybe two things. 1) Crud in the touch hole or on the breech plug face, and/or 2) wood rubbing against the internal lock parts as the lock is fired.
I will keep you all advised when I have figured it out.