When shopping for black powder firearms, the most common choices are the reproductions by Italian manufacturers. They have all had quality control problems from time to time, some more than others. Most of the quality issues are minor finishing issues with Uberti and Pietta. As for the others, they had the same problems, along with soft metal internals.
Uberti is the best of the Italian black powder firearm manufacturers. hey are known for their high quality, especially the older black powder firearms. Uberti is known for high workmanship, better parts and quality control. That being said, they have quality controls problems just like any other manufacturer. Their quality is still good, but quality control seems to be slipping.
Pietta offers good value for the money as far a quality goes. Be careful buying Piettas manufactured before 2003, their quality varied , but most older Piettas are good quality. Newer Pietta firearms are just as good as Uberti in quality is the word being heard from Pietta owners today.
Then there is Euroarms, formerly known as Armi San Paolo. They had issues with soft internal parts from time to time.
Armi San Marco was another Italian manufacturer that went out of business in 2000. They have varying quality with soft internals. The 1858 Remington style ASM’s were rather decent revolvers.
The companies often share parts and do contract work for each other. Quality of these firearms is best judged on a piece by piece basis, if possible. If not possible, do as much research as possible on the firearm you are considering. The more you know about the black powder firearm of your choice, the better off you are.