I looked at a 6” 686 today. There is a small air gap (can see light) between the barrel and frame. It is thin but I didn’t measure it with a feeler gauge. Is this normal? I’m guessing when setting the gap between the forcing cone and cylinder the only adjustment is how far in you turn the barrel when torquing it to the frame. So the gap (if noticeable) is dependent on the placement of the starting threads on the barrel and within the frame. In order to not have a canted barrel and get the forcing cone-cylinder gap correct (0.003-0.006) you end up with a gap that reflects the lack of these considerations when machining. It seems it would require some forethought to start the tapping process for cutting the threads. Any advice as to what one should expect?