Thanks for the diagram. That helps me a lot on understanding the different parts. Maybe someone else will come up with more information, or even better maybe somebody out there has experienced this issue too with the cylinder wobbling side to side and moving more than usual from front to back, and knows the solution to fix it. I do not have to disassemble the entire gun. I only have to fix the cylinder and related parts.
This old Charter Arms Undercover has served me well for years. I am going to make the repair of the Charter Arms Undercover 38 my summer project. If I succeed I will have learned something along the way, and will feel more comfortable with future projects. If I fail then I pack it up and send it off to Charter Arms for repair.
Meanwhile I just bought a S&W Model 642 to replace the Charter Arms for a while. I am retired and need a 38 special here on our mini farm to take care of poisonous snakes during the summer months. From March through November each year I usually will kill from 12 to 20 poisonous snakes around here.