Nice 6 shot group. My little .32 flint also does this at 25 yards with a .311" Lee ball and .022" (14ounce denim) patch. I then moved back to 50 yards and found I the 20gr. charge was useless at that longer range, shooting over 2". I tested 25gr. then 30, then 35gr. where I got 2 consecutive 1" groups of 5 each- different targets. Increasing the charge further, to 40gr. opened the groups, 2 consecutive 5 shot groups to 1 1/2", so 35gr. was it for a water based lubed patch.
I then experimented with Mink Oil and Neetsfoot Oil and had to use 40gr. to get the same accuracy of 1", as with the water based lubes - all the while using the 10 ounce denim patch (calling it .022").
I have not finished experimenting with the heavier mattress ticking, other than to check and see similar results, even with the .320" ball. My barrel has very narrow grooves, exactly the opposite of what I like. I am considering putting a GM bl. on it.