The cannon is a 3" Mk 21 (or thereabouts) WWII vintage gun. We're looking for information on creating salute charges. Used cartridges are available and we're assuming that the primers will be 209 shotgun primers. A tool can be made if necessary to ream the primer pockets to fit a 209 primer. If possible, the operators would like to avoid using black powder because of the cleaning issues on a 3" bore/150" long barrel.
Does anyone have first hand knowledge of making workable salute charges for a 3" naval gun or similar fixed ammunition gun? The less particulate matter leaving the barrel, the better. We don't know at this point where the gun might be fired. This is for a gun mounted on a retired US Navy ship.