7mm Winchester Short Magnum

The 7mm Winchester Short Magnum is a centrefire cartridge developed in partnership with Browning Arms Company and Winchester ammunition, making its debut and introduced to the shooting public in 2001. Wikipedia
 
Case length2.100 in (53.3 mm)
Rifling twist1 turn in 9.5"
Parent case.404 Jeffery
Bullet diameter0.284 in (7.2 mm)
Neck diameter0.321 in (8.2 mm)
Base diameter0.555 in (14.1 mm)
Shoulder diameter0.538 in (13.7 mm)