I've had a set of Briley Companion tubes for about 10 years that I've never used. I have an older English sxs I'd like to try them in, its a 12 and the tubes are 20. I know about the balance etc. but I'm curious as to whether they may only be used with a gun they are fitted to or not. They fit in the gun I have very snugly and the extractors work. Anyone have any problems with them?