Jeweler
The material you want is Melton Baize which is a wool cloth not a felt and harder wearing used for Snooker/Pool tables.
In the photograph is what a Victorian poacher cum Gamekeeper used to hide the fact that he had a gun when he went out in the evenings to do a little business. The gun fits the Violin case with no room to spare though the case is of rather low quality Victorian manufacture but the gun is an Adams a sound London maker. The handle and catches where replaced so I could use it to transport another guns. Well who would give an old Violin case a second look?
