Need one of the old style w interrupted thread, for an R25 tang sight but I am thinking the stems fit multiple bases. Lyman has discontinued this style of sight, their current stems have complete threads. I suppose I could make one but don't have anything to copy. Any help would be appreciated.

FWIW there is no source for parts for these older Lyman sights, other than Ebay etc. I did find a guy in MI that used to work for Marbles, who said he might have a stem. But even he told me it was impossible to find the stems with the little internal folding aperture, he only had one with a screw-in aperture. I also found, on Buffalo Arms, an aftermarket stem made by Red River with windage adjustment, spendy and only worth while for a pretty sophisticated setup. In my case, I just need a simple sight for a Rem 25 that I use for pest control on the ranch.