On page 843 of the "Handloaders Manual of Cartridge Conversions" they call the cartridge the 7.62 RussianNagant or 7.62 Nagant Revolver as well.
bullet weight- 100 grn
type - lead
powder - 3.8grn Bulls Eye
velocity - 900fps
make from - 32-20 Winchester. Taper expand to .300 dia. F/L size. Square case mouth. Chamfer and fire form. Case is short, but OK. You may also re-body a 38 acp with 11/32 dia tubeing and f/l resize. Use andy 30 cal mould to produce 150grn projectiles and cut to equal 100 to 105 grains. Seat bullet to completely inside the case and apply roll crimp to case mouth. It may be necessary to turn the 32-20 rim to the .388 dia.
case type - rimmed straight
case length - 1.52in
head dia - .358 in
Rim dia - .388 in
neck dia - .296 in
body angle - 1.2 degrees
case capacity - 1.83 cc
loaded length - 1.52 in
primer - small pistol
case capcity - 28.3 grns water
I hope this helps a little, bearhunter