9 x 23 brass will say "9 x 23", "9 supercomp", and sometimes "9 x 23 Winchester"......and maybe even a couple others that I can't think of...... first open gun I bought my wife was in this caliber. Just FYI, if you haven't decided to do it yet,save yourself some headache and go with 38 super. Cheaper, MUCH easier to find brass, and much more tried and true recipes for various loads. There really isn't one particular comp that is better than another, all in all.... I like the EGW comps and the Brazos comps. ( I have two guns with the EGW, and one with the Brazos). The Dawson comps are nice, too, so it's gonna be personal preference. I'd say build a 5" gun w/ and EGW comp as a starting point, and then you have a base to tweak from there. That's just my .02, of course...........
-Mike