That (that the forcing cone/ cyl. gap is too tight) is a likely cause. However, it is NOT the only possibility. When you say that the cyl. won't turn, do you mean that it is bound up ? Or, can it be turned by hand with little resistance ? If the cyl. is bound up, the the problem is probably tight clearance. You can check this visually, as well as with feeler gauges. If the gap looks really tight, as in thin as a sheet of paper tight, then the gap is probably too small.
What you said about wiping off the front of the cylinder temporarily freeing up the cylinder is significant - and MIGHT be clear evidence of the gap being too small.
However, another possibility is that the cylinder is binding internally. Tauruses are funny, different from Smith & Wessons for example, in that the cylinder does not free wheel - and thus is more resistant to being turned, even when nothing is wrong. Does the cylinder turn freely when open ? Try turning it also, when open, while pulling toward the rear....then again while pushing forward while turning it (while open). If no binding is detected, then this possibility can be eliminated.
Finally, if the cylinder can be pushed forward and rearward (when closed) a significant amount.....more than a few thousands of an inch....then this could potentially be the problem. This "slop" is referred to as end shake - and it can cause a revolver cylinder to skip timing and not index to the next chamber every time it should. It can also cause a cylinder to turn only part way to the next chamber. Do check for excess cylinder movement. This is the least likely of the possible causes of your problem - but it is possible.
Based on the results of these tests, you should be able to diagnose the problem yourself. Being that the gun is a Taurus, some gunsmiths won't touch them. So, you might end up having to send the gun back to Taurus for repair. If the forcing cone simply needs to be cut back (to enlarge the gap), this can be done by you, with the right tools. But, don't attempt it yourself without knowing how it should be done properly.
Hope this helps.
By the way, the function tests described above are the same for every brand (and model) of revolver.