I believe the MCT in CLT for domestic US flights is 30 min. There are probably numerous exceptions though.... The MCT's are based on passengers not baggage. Baggage usually can make it faster then passengers, hence all the stories of people missing flights and their baggage making it. I find the MCTs are almost always accurate even in the case of unusaul connections (i.e. AA-US in MCI), however arrival times may not be.