Thanks for the additional pictures, and for confirming the material from which the powder measure was made.
From the 5th and 6th photos in post #81, the lead balls look to be a little over 5/16". Five-sixteenths of an inch would calculate to 0.3125", so the balls would be a little larger than that. I understood your mould has the number 95
on it. I got out my chart, and a 95 gauge ball (that is, 95 balls to the pound of lead) would measure 0.366". I would be very interested in the actual bore diameter of the rifle, as it seems very likely that your lead balls, mould, and rifle are old companions. Most round ball shooters now like to use a ball 0.010" under bore diameter, but it is generally believed that the old-timers used slightly smaller balls relative to bore size. The difference between bore size and ball size is described as "windage." It is pretty rare to find an old rifle that still has its original mould with it. If you can get accurate measurements of the ball diameter and rifle bore size, we can calculate the windage and get a better understanding of how the old-timers loaded and shot this rifle. It would be great if we could get an accurate measure of the amount of powder thrown by that old charger, too. And for the truly obsessive, a measurement of the patch thickness.
A lot of us carry so much with us for shooting. That little powder horn with the attached charger, the brass container with tallow, patches, and balls, and a tin of caps could all be carried in a coat pocket for a day afield. There is a lot to be learned from this collection!