Fella's;
I've not done a search, but I'm guessing that what the OP's issue is, is that there are no 6mm Remington cartridge guns in current production. At one time in the not-too-distant past, that same situation applied to the .220 Swift. The Swift remains alive and well and I think the same will also be proved in the case of the 6mm Remington.
Ruger has a well documented habit of producing runs in calibers that have been out of production for a bit, the .257 Roberts being an excellent example.
I've never had a problem getting components to roll my own, and regard questions in that regard as mere "crying wolf". It's simply too good a cartridge to disappear. Good grief, even the Winchester .284 re-emerged as the 6.5-284!
900F