An instructor friend of mine, from Texas once said; you don't feed an entire bale of hay, to one cow. We got a good laugh out of that and understood what he meant even though most of us XXX Yankees had never had to feed a cow. I can tell you are going at a good pace as slow and easy is going to win this race. At some point you are going to drop a bore-light and get a better picture of what your next move will be. There is a variety of lights, you can use and one is a Bobber-Light sold at Walmart. I prefer the amber. ….Or would you just shoot it and use bore lapping as a problem solver later if it’s needed.
I'd clean it and shoot it. You may can fire a few loads and burn some of the rust out.
^^^^ THIS ^^^^I probably will shoot it...
..... oh..... yer jus' gonna LUV flintlocks