The way you had it written I took your post to mean a Nagant INSTEAD of.
As a piece of history, they're interesting, but not in place of a better gun.
The "civilian" stuff is typically watered down & the Russian stuff will be dwindling, as I said. In both, the full metal jacket is not the most effective bullet type for defense.
The civilian ammunition can be hard to find, too.
If you want one as a toy, by all means go for it.