There is a small group of guys that shoot 8ga Damascus guns on a regular basis. We have dedicated 8ga competitions at Hausmann's, The Spring Southern and Rock Mountain. Loaded shells for kiln guns will not fit in sporting guns due to a ring at the base of the hull that prevents it from chambering. There is no one currently commercially loading 8ga for sporting guns in either the US or UK. Your only option is reloading. Components and recipies are readly avaliable. If you want to persue reloading first search the subject on the Parker forum and if it still sounds like something we want to do contact me at superfoxcollector@gmail.com and I can help you get started.