I've had several flats on the same wheel (rear wheel only, kinlin xr-300 if that helps), where the hole in the tube is on the section that touches the rim (the inside portion of the rim, the part farthest from the tire).

I can't feel anything through the rim tape (Kore tape), but i've just had my third flat. They're all happening in different places relative to the valve, so I can't figure out what's going on. Should I try different rim tape?