Run the #30 one more time to make sure you're not hung on a burr or something. Tighten up the hose clamp to help squeeze it but not too much, you don't want to break the clamp. Then use the dowel to help it along.
Mine were not exactly a precision fit. If you had to go to a #29 to get it to seat fully, for example, I don't think that would be a real problem.