Hi, Sir William and guys,
The .32 S&W Long is really too small for the Nagant and .32-20 is too big. There is reloadable ammo but it is not always available. One way out is to buy one of the .32 ACP cylinders. I got one and reamed it to take .32 H&R Magnum. It works fine, even though the .32 Magnum is a pop gun round compared to the original Nagant military load.
They are a lot of fun, and well worth the very reasonable price. BTW, the originals all had wood grips; the plastic grips are modern, put on when the guns were arsenal overhauled, meaning they ground off the rust, gave the guns a quick tank bluing, and stuck on new grips.
Sir William is correct as to two models, but it may be noted that they look exactly alike. The only difference in the two Nagant models is that the DA hammer strut was removed for the single action (enlisted) model. After about 1924 the Soviets dropped the distinction and at least some enlisted men's models were converted to the standard DA.
I doubt that the Russian winter had anything to do with the unique cylinder seal. The design was Belgian, and was fully developed before the revolver was submitted for Russian trials. It was a case of the Russians letting themselves be suckered into paying extra for a solution in search of a problem. The Swiss and Swedes, no strangers to cold, didn't see any need for such a thing.
Jim