Dear EOD, there have been several threads on various websites on the development of the “8mm Nagant Rifle” of 1890, with the cartridge being partly derived from the 8x50/53R Austrian; There is also mention of a “8mm Lee-Nagant” cartridge, also rimmed (?8x55R?).
The Nagant Bolt action rifle did contribute some design features to the Later M1891 Mosin., whilst the Cartridge (7,62x54R) seems to be more “Russian” than “Belgian”. Maybe “pragmatism” such as calling the Rifle, Vintovka tre linie ( Three line Infantry Rifle) sounded better than “Three point One-Five Linie” ( .315 == 8mm; 3 linie= .300" ( 1 Lini = 1/10 "). Even when the USSR adopted the Metric system in 1918-20, the Rifle was still called “Vintovka Mosina tre Linie.” by the troops.
The Long Neck on the 7,62 case was due to the use of the 210 grain round nose cylindrical projectile, to support the long projectile ( stop “De-bulleting” during handling.). When they adopted the Light Ball (spitzer) in 1908, they could have shortened the case (Neck) to 52mm or even more, but did not.
The whole matter of the development of Mosin’s rifle and Cartridge, the amount of Nagant’s contribution ( Prototyping, etc) and leading to Greenwood and Batley doing the final Engineering designs (in Imperial Inches, and with Withworth threads), and then supplying specialised Machinery to make the MN91, is one of the mysteries of the gunmaking world. ( G&B had already engineered and tooled up Tula for the Berdan II, with BSA doing a “Machinery proof” in the 1880s; it seems that Chatellerault did the 1892-3 “Proof” of the G&B Machinery before it was shipped to Tula and Ishevsk and Sestroryetsk. ( some of the Berdan Machinery was also modified by G&B to suit the MN manufacture.). G&B also supplied Cartridge making machinery to the Imperial Russian Gov’t.
An area with la lot of research to be done in three languages, Russian, French and English. French was the “official” Language of most higher officers of the Imperial Army ( it was used at Court) so they tended to go the Belgium for Ideas (MN 91, N 95 revolver,etc.) and of course, The Belgians utilised G&B for Machinery from Britain and the USA ( as well as from Loewe of Berlin).