I had considerable experience with top breaks as a kid when they could be had for $1.50 ~$2.00 from junk shops and second hand stores.
The biggest problem with them was worn frame lugs where the latch slid over them in closing and latching the revolver. These wore to a rounded surface and the gun jumped open when fired. A welding shop or garage could build these up with weld metal or even a brazing rod. We could then file them back down to square and have a revolver good for many more days of shooting.