While I understand the desire to shoot it, the unknown condition inside, as well as the drum issue would probably have me very very cautious. If you must shoot it, tie it down to a bench with a small powder charge in the barrel, tie a string to the trigger, and hide behind something when you tug the string. If it stays intact, call it a success and put it on the wall as a display piece.
So many safely shootable guns out there, risking damage to an original or injury to a person doesn't make sense.
