A general note on "gussying things up." Occasionally I get a gut notion that many of the concerns that blackpowder enthusiasts have regarding precision, ignition time, barrel accuracy, etc. are overblown and sometimes imaginary. I've had people tell me that some of our noted custom barrel makers produce barrels that "don't shoot" but with special personal re-rifling they are tack drivers. I ask, how many people would notice the difference that you supposedly created? I would believe this only if I were given a pre and post test opportunity to shoot the rifle myself. A bunch of targets shoved in my face tell me absolutely nothing other than that you have a point to prove. I apologize for my blatant skepticism. Anyway, how many people can hold that tightly, offhand with a flint rifle? I want to see it with my own eyes. I have served on my Commonwealth's high power rifle team, and I have heard many testimonies and "fish stories" that did not prove out on the firing line, and ours were minute-of-angle tuned service rifles used by skilled marksmen who knew what they were doing and were where they were because they beat the competition for a slot on the team.
If you buy a Chambers lock or Getz barrel, it should work out of the box. As you apparently found out, you run the possibility of magnifying a problem rather than "fixing" it. Just last month I had to refit an otherwise decent lock that a clown "stoned' out of timing. Just had to lighten that trigger and make 'er better. If, for some reason, you encounter a problem, talk to the vendor. They have a reputation of keeping happy customers. Your lock left the maker's bench with that tiny gap because they concluded that it was unimportant. Just my take on things after reading about all the fiddling with the functional. On the other hand, this gives work to those of us with a bench.
JWH