I have also used Windex (with Ammonia) on old mil-surp bores and it seems to really help clean them up. First I use GI bore cleaners and brushes to get the loose gunk (powder residue) out, then saw it dry, then soak some patches with Windex and run them down the bore until I am sure it got a good soak, the use a clean or new brush, more windex patches and finally dry patch it until it comes up nice and shiny.
You need to understand that over the years there has probably been a lot of copper fouling buildup in that bore. It is darn near microscopic and not something you can detect easily by eyeball, but it is there, so you are not likely to remove it all in one cleaning session. And a lot of guys forget that hunting ammo is also jacketed and will cause copper fouling buildup just like mil-spec ammo, so the guy who shoves his huntin' rifle back in the closet after only firing 3-5 shots that year isn't really doing himself and favors. jmtcw.