The National Safety Rules and Procedures for Shooting Muzzleloading Artillery, as adapted by the American Artillery Association, states that "mortar beds shall permanently restrict barrels from raising above 75 degrees from the horizontal." Do any forum members compete in AAA shoots, and if so, how are you PERMANENTLY restricting your barrels from rising above 75 degrees in elevation? I have a couple of commercial beer can mortars and a golf ball mortar and all the barrels can all be raised straight up and even past vertical.