I did some research and from what I can see, Leupold makes a 1" tube and a 30mm Tube, but I didn't see anything smaller than 1". 1" is about 25.4mm, so a 30mm tube is obviously larger than a 1" tube. Is it possible the rings you have are for the 30mm tube, thus causing the tube to appear smaller than 1".
also, can you provide some detail about the scope, model, what size objective lens, what power is it. Actually the model will be suifficient to quickly identify the tube size.