What is the maker of the 10ga. When was it made. If it was made in the late 1800s or early 19s than unless it was altered it probably was chambered for 2 1/2 or 2 7/8" shells. Are they Damascus barrels or steel barrels. Without knowing the answers to these questions you would probable be better off leaving it in the closet. (you should probable have the barrels measured for chamber length and barrel wall thickness).