Hello I have a one foot pellet pipe where the inside tube diameter is 1/16" less than 3 inches. It goes onto the Pelpro stove vent pipe just fine. So to do it right I bought a pellet stove appliance adapter by duravent. Not the Duravent pro line. This adapter has the rop gasket like all the other pipes. Now the adapter inside pipe measures very close to 3 inches and does not fit inside the stove vent pipe??? Should the adapter be crimpted with HVAC crimpers? Am I missing something here?? Please advise. See pics below.