stopper

This kit came with the bike when I bought it. It has an orange o-ring, a flat rubber stopper (guessing at what you'd call it) and a metal ring. The ring is about the size of a quarter. I'm having difficulty figuring out how that ring will do anything to stop the o-ring from being blown out...

Does anyone know if the rear exhaust stopper ring is supposed to be a tight fit on the pipe and hold the pipe in? It is #6 on bikebandits schematic for a 95 Vmax. Mine slips on and off easily and I just installed a new gasket (#5). I tighten the muffler band really tight and I can pull the...