I've been asked for advice by a deer client on either buying or loading blank shotgun cartridges for use on 'wassailing' night. At the height of the celebrations there is a mass feu de joie of shotguns, but the cartridges they've tried aren't very impressive. As it takes place in a cider-orchard, they don't really want to use live ammo. What he's after is a cartridge that will give a loud report and a robust gout of flame. they don't have the resources for a couple of dozen blunderbusses, so in the absence of that recourse, has anyone a suggestion on a safe and effective substitute?