One thing to mention here is that the quality of manufacture has not been the same for all iterations of Charter Arms. It is possible that broken transfer bars (which really should not have any reason to fracture under any kind of operation, much less dry fire) are due to a manufacturing defect.
I have an Undercover from the first iteration of the company. I picked it up used 3 years ago. Since then I have dry fired it about 300 times a month on average just working the action while 'listening' to useless conference calls. I have never had a problem, nor do I anticipate one.
The reason why you see some warnings about dry fire on centerfire revolvers is that back in the day the firing pin was directly attached to the hammer. The connection between the two components is small and thin and is a stress concentrator, as is the case with my 10-4. Under excessive use the connection could fracture. This really was the case back when steel hardening methods were more uncertain and the chances of forming brittle steel was high.
Now, that is wisdom from long ago, and it really didn't even apply in the 60s. Neither myself, my father, my grandfather, or either of my great uncles have broken or have seen a centerfire firearm broken due to dry fire and we have all been avid shooters.