Yes, Jacques Littlefield did it all the time when he was building the tank collection, however there are constraints. And one of them, especially for combat vehicles is that they are 'demilitarized' which generally involves some damage that would render them unfit to use in a fight. As I recall one of their tanks had the barrel cut off and then re-welded back on with a slight offset. Any attempt to fire it with a shell would cause the barrel to explode in a backfire. However some black powder and wadding was OK which gave a satisfying 'boom!' and smoke.