Need to ID old nagant revolver

[old nagant]

I have a 6 shot revolver with a 1 11-16" octagan barrel, a .38 S&W short fits in with SN 731 on it. It appears to be a belgian made Nagant. I would like to find out the model and year if possible. Thanks

 

[James K]

Pictures? Proofmarks? Not enough info.

Jim