I need to replace the bottle cage mounts on a TI frame, so I purchased some M5 rivnuts. However, when I tried to put the nut into the hole in the frame, it doesn't fit! I tried lightly tapping it in with a hammer but it's definitely too big. it seems like the rivnut couldn't be much thinner or else it couldn't hold a decent thread.. actually that may be the problem with the existing mounts since they are all stripped.

so.. Do i need to drill the hole bigger? sand down the riv nut? order the proper size? these ones are 7mm in diameter according to the package but it seems I need some 6mm ones