While the Russian carbines and rifles were Mosin-Nagant collaborative works, the Belgian brothers Nagant were solely responsible for the 7.62x38r 1895 Nagant revolver made from before WWI to the end of WWII at the Russian Tula and Izhevsk plants.
I have been producing homebrew ammo for my meager collection of Nagants for several years now. In retrospect, I would rather have bought just a bunch of Ruskie 'target' loads, as anemic as they were. My loads, in a .32-20 case sized by a Lee carbide M1 Carbine sizer, don't 'jump the gap', making clean-up of the chamber concave exits and convex barrel entry problematic. Certainly, if I could find the 'Hot Shot' Nagant ammo today at a fair price, I'd likely stock up on it instead.
Those homebrews started life with new .32-20 brass, to which I'd take ~.010" off the headstamp - and turn ~.024" off the rim's OD. Sure, you could mill the breech block and turn some - ~.015" - from the inner OD of the pawl-engaging ground area. I'd rather leave the revolver stock - modify the ammo cases to fit, as tedious as it is. I shed a tear when a case is lost...
The aftermarket .32 ACP cylinders don't fit well - may have to be modified to even work. The ammo is more anemic - and certainly not inexpensive. Some use .32 S&WL ammo - like the soft-cased MagTech - which will bulge to the point of splitting several cases per 7-shot cylinder - be careful. Certainly, the usual .32 S&WL/H&RM ammo is straight walled, while the chamber is tapered very similarly to an M1 Carbine round. I feel .32 H&RM ammo is dangerous in this application and should be avoided, no matter what some of the surplus dealers have suggested.
I had my C&R FFL renewed this summer - I have only used it to buy a couple of my Nagants, the earliest units bought like anyone else - via delivery to a local gunstore. They are neat - and did come with a reversible straight blade/wood handle that fits everything on the revolver, a cleaning rod, a lanyard, and a serviceable holster. All were in VG++ condition, too. Sadly, the re-arsenalled revolvers have a little finish buildup on the working parts, making the high DA pull even worse. Tweaked, they still approach 20# DA pull - certainly not a S&W. Of course, there is a lot to go on in a trigger pull.
If you buy one - go to the 1895 Nagant sub-forum at Gunboards.com for more info - even dissection info. Neat piece of Victorian engineering. Get the Serbian made 'Hot Shot' ammo. Have fun!
Stainz