This is the place for musket rifles, right?

My mom's dad used to own this rifle that her uncle decided to pass to our ownership for some odd reason. It's early 19th century rifle that doesn't work anymore. Out of curiosity, I would like to know some info about general rifle specifications. I think the muzzle is between 1/1 and 1/2 inch across but that's all I can say. . It doesn't have a gun manufacturer listed on it,
so my limited knowledge of gun history tells me it was made by some guy in a shop. If you can give me some generic rifle stats, I could use it to figure out what sort of balls were fired from it which is what really makes me curious.

To help, we need more information. Is it a percussion gun or flintlock? Octagon or round barrel? Patchbox or no? Approximate caliber (measure the bore with a ruler if you have to)? Got any pictures that can be posted? These would all help!