The case head of the .32 S&W/H&R is about the same size as the case diameter of the Nagant cartridge, so the case head will sometimes actually end up moving into the chamber, thus preventing an adequate primer strike.
Due to the similarity in size between the .32 S&W/H&R cartridge case head and the Nagant cartridge's case diameter, there is a risk of the case head getting stuck in the chamber, preventing a proper primer strike.