.41 Remington Magnum

The .41 Remington Magnum or 10.4×33mmR as it is known in unofficial metric designation, is a center fire firearms cartridge primarily developed for use in large-frame revolvers, introduced in 1964 by the Remington Arms Company, intended for hunting and law enforcement purposes.Wikipedia
 
Bullet diameter.410 in (10.4 mm)
Case length1.290 in (32.8 mm)
Rim diameter.492 in (12.5 mm)
Case capacity34 gr H2O (2.2 cm3)
Neck diameter.434 in (11.0 mm)
Base diameter.434 in (11.0 mm)
Rifling twist1-18½ in