Jim,
I checked my gages today. The 243 Win is a Forster set and the length is marked on the gage (.004 difference). JGS gages are also marked for length on the gage and the difference is .006 for .308 Win and 6.5x55 SE. My 06 and belted mag gages are Clymer and are not marked but from my measurements today they both apear to be .006. The only rimmed gages I have are 22 rimfire and although they are JGS they are not marked for length. I didn't have a chance today to measure them.
George