Thanks to all who provided info on this topic, but I'm still having problems. I'm encouraged by Misfit's success, as it sounds like he was having the exact same problem with the same gun (50 cal GPH). Swabbing with alcohol just didn't work for me GaCop, not sure why, still extremely tight. Cleaning with hot water after the first shot was better, but that's a pretty thorough cleaning and interestingly even then I could notice that the second ball was a little harder to seat than the first. I then tried butch's bore shine and had better luck, with each subsequent shot seating about like the first one, but that was with a pretty thorough cleaning that wouldn't be practical when needing to reload after shooting at game. I'm noticing that there's a lot of hard junk on my first couple of cleaning patches. I'm only up to about 50 rounds through the gun so maybe it will settle down and start grouping soon, but boxes of GP Bullets aren't cheap so I think I'll spring for a mold and start casting my own. Trying to decide between the Lee REAL and the Lyman Plains bullet. Bull3540 I will try the wonderwads, thanks for that tip.
BTW, I can see the perpendicular striations on my rifling that some have mentioned. Is this death to the barrel or will they smooth up over time (I'm wondering if that is why my fouling is so bad)? I did lap the barrel with steel wool, about 200 strokes. Might that help with problem and should I give it some more of that treatment? Spikebuck mentioned JB's and I'm wondering if I should give that a try.
Any additional wisdom would be appreciated guys. I had a CVA mountain rifle in the 70s when I was a teenager and it was a good RB shooter, but I sold it in the early 80s when I got interested in other things. I experimented (unsuccessfully) with a Mississippi in the 90s, then bought a nice flintlock, but then life got complicated again and I haven't shot it enough to come up with a tack driving recipe. I want to get this GPH shooting good with a big conical so I can use it for elk, then go back to my flinter and get it figured out. It's nice to be back into BP again at 53. I'm extremely impressed by the knowledge of the folks on this forum.