if i buy a building at 5% cap rate at a discount, is it still 5%?

[Jim Growfer]

If someone is asking 600k for a building that has a 5% cap rate, 30k NOI and i purchase it at 500k. It wouldnt be 5% anymore, correct?

Cap rate confuses me a little bit, because that cap rate would now be 6% not 5%.  

Where am i wrong?