Hi,
If you are talking about the 1895 Nagant gas-seal revolver, it was designed by the Belgian brothers, Emile and Leon Nagant. They were well known designers that had favor with the Imperial Russian court and military. After having their magazine/cartridge interrupter design incorporated into the 1891 Mosin-Nagant.
The Imperial Russian Army was the only major military to adopt and use the gas-seal design in large numbers. A few were sold and used by Norway, Sweden, Greece, Poland, and of course some civilian sales occurred also. Though these would be pretty rare to find in the US. But Russia was by far and away the biggest producer and user of the Nagant revolver.
To determine where they were made, you will need to look at the proofmarks. A star means Tula, Russia, A few were made by Izhevsk also. They have an arrow in a triangle mark. A Belgian proof will probably be a crown over an oval with the letters LEG inside.
As is normally the case, post some good photos of the markings when you get them. We can then determine where and perhaps what era they were made.
dalee
