I passed stones wich were about 2-2,5 cm diameter without any problems at all. I will soon post photos of those monsters here on curezone. I still keep them in my freezer as my biggest trophy.
Another interesting thing I found out lately. I was eating boiled liver of a young goat. The goat weighet about 20 -25 kg. I found that some ducts, not even main ducts, of that liver were from 3 -8 mm in diameter! And we are talking about 25 kg heavy goat! So expect human ducts to be double in size. I took photo of some fragments of those goat ducts.
I will try to post the photos today or tomorrow.