Case lining cloth ---- I prefer wool -- look out for "felt", some of it is dyed with salt mordants and will rust hell out of a gun. Good wool can be bought at fabric stores, but at quite high prices. On the other hand, if you go to a "thrift" store with used clothing, you can usually find a ladies winter coat in dark blue, red, or green for a few dollars. One coat will line 2-3 gun cases. I glue the wool in by brushing carpenter's wood glue onto the wood with a brush with the bristles cut short. A light spray of "Scotch Gard" will help prevent soiling of the wool. This cloth is a little thicker than baize, but lies smoothly when glued to the wood, and offers a little cushioning.
I usually have done the exterior with leather, or most often with heavy cotton duck, also glued on. Trim, edges, corners, etc can be covered with leather, stitched on thru the wood. Be sure to make a groove on the inside of the case to accommodate the stitches.
Hardware is always a problem. Sometimes the above-mentioned thrift stores have high-grade luggage or briefcases with good hardware that can be salvaged.
CHRIS