If the term "accuracy" is in your dictionary, you might consider something other than a Nagant. They are accurate enough by "minute of German" standards, but the trigger pull and handling keep them from being anything like target revolvers.
The Russians used them for target shooting and the armorers did their best with them, but I am afraid the words that come to mind involve silk purses and sows' ears. In one international competition some years ago, the Russian team conspicuously practiced with Nagant target models, to the amusement of the other shooters. When match day came, the Russians turned up with S&W K-38s and cleaned up.
Jim