More like somewhere in between, really.

Not 100% confident on how people pronounce "cock" but it's definitely not close to "caulk".

Being a french speaker, I would say pronunciation is closer to "puck" with a k, so go with "Kuck".

In my idiolect, those two words are homonyms. When I worked construction, you couldn't ask someone for caulk without raucous laughter.

http://dictionary.reference.com/browse/caulk

this link seems to agree, with the word represented in IPA as [kɔːk]

More information about who in the US has and hasn't merged those two sounds: https://en.wikipedia.org/wiki/Phonological_history_of_Englis...

It's the cot-caught merger.