The barrel was new as of early 2023. Colerain round groove 58. Shooting cast balls with all balls in a 1gr range. 0.570. all balls look great.
Patches - bull denim (0.020), 12oz (0.022/3), duck canvas (0.022/3)
Patches measured using Daryl's caliper method.
Lubed with TOW mink oil, saturated. Have also used hopes BP cleaner as range lube
No patch/lube combo seems to be better than another. They all require a short starter and are tough to start.
No patch damage on loading. No patch damage post shooting the last time I looked at a few.
The barrel was super rough on the lands as new. It's taken many rounds of grey 3m pad and 0000 steel wool tight on a jag to get it smoothed out. It used to be that the first load on a clean bore would go down ok, but tough. Subsequent loads would get worse and worse and eventually would have to be hammered down. Now, it is tough for the first 4-5" and then it goes down easily, nice and smooth until it gets to within a couple inches of the bottom and then gets rough, I think from fouling ring. Loading on a clean barrel the breech portion is smooth.
The lock is a chambers late ketland and seems plenty fast. I use 2f schuetzen for main charge. I've tried everything from 65-140gr and there's nothing that seems to produce a consistent group.
Picture is last time out at 50 yards. All load parameters the same except charge weight. Lower left target has 2 extra shots (high) from different patches. I am fairly certain that I'm not flinching enough to cause that much inaccuracy at 50.