Some websites can redirect you, but they're not using http 301 or 302. After that the url will be changed and you can't go back to the previous page using your web browser's back button. For example, ign.com redirects me depending on my ip, the page automatically refreshes and its url becomes www.ign.(country name). In firefox's network console I never see http 302. It just changes to the new url and sets a cookie marking where I'm from. It's not exactly 'refresh' either because disabling auto refresh in about:config has no effect on this.
So what kind of web technology is this and how can I disable this behavior? It's quite annoying.