in millimeters (mm) plus Imperial (inches). Americans would define the shoulder angle at alpha/2 = 20 degrees. The common rifling twist rate for this cartridge is 229 mm (1 in 9 in), 6 grooves, Ø lands = , Ø grooves = , land width = and the primer type is large rifle. According to the official C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) rulings, the .260 Remington case can handle up to piezo pressure. In C.I.P. regulated countries every rifle cartridge combo has to be proofed at 125% of this maximum C.I.P. pressure to certify for sale to consumers. Performance The .260 Remington being a .264 caliber (6.5 mm) has certain advantages: the bullets have good sectional density (penetrating ability) and a good selection of bullet weights. Factory ammunition usually are loaded with bullets weighing anywhere from to . Bullets available to the reloader range from to . The bullet has a sectional density of 0.246 which is similar to a .308 caliber (7.62 mm) bullet. The bullet has a sectional density of 0.287 which is similar to that of a .308 caliber (7.62 mm) bullet. The bullet which has a sectional density of 0.328 is similar in sectional density to a .308 caliber (7.62 mm) bullet. As sectional density plays a large factor in penetration, the .264 caliber (6.5 mm), though a diminutive caliber from a North American point of view, has had excellent results in the field. Walter D.M. Bell, who was known to have shot over a thousand elephants in his lifetime, used, among others, .264 caliber (6.5 mm) and .284 caliber (7 mm) rifles to do so. The .260 Remington, while having a slightly lesser case capacity than the 6.5×55mm, is loaded to higher pressure levels. The opposite is true when comparing the .260 Remington to the 6.5mm Creedmoor: They are nearly-identical but the Creedmoor can take a higher chamber pressure than the .260 Remington, leading the Creedmoor to have more room for a longer bullet (more aerodynamically efficient, higher sectional density than most shorter bullets) in a given magazine length or cartridge overall length than the .260 Remington's maximum projectile length or ogive length, and yet the .260 Remington only has a similar muzzle velocities as the 6.5 Creedmoor for a given projectile weight, despite the .260 Remington's larger case capacity and longer brass casing. However, for the same reasons (higher