Lee Undersize Mandrel .3035in LEE. Should you desire a tighter fit you can order this (.3035in) undersized mandrel for 300 WSM 7.5x55 30/06 30/30 308 Win and 300 Win Mag. Specifications for Lee Undersize Mandrel .3035in: Manufacturer: Lee Caliber: .30-30 Winchester 7.5x55mm Swiss .30-06 Springfield .308 Winchester .300 Winchester Short Magnum .300 Winchester Magnum Weight: 0.06 lb Length: 0.3035 in Gun Type: Rifle Package Contents: Lee Undersize Mandrel .3035in Lee LEE90480: Undersize Mandrel .3035in