 Americans would define the shoulder angle at alpha/2 = 29 degrees.The common rifling twist rate for this cartridge is 200 mm (1 in 7.87 in), 6 grooves, Ø lands = 6.45 mm, Ø grooves = 6.70 mm, land width = 3.50 mm and the primer type is large rifle magnum.According to the official C.I.P.