The .408 Cheyenne Tactical (or .408 Chey Tac ) is a specialized rimless bottlenecked centerfire cartridge for military long-range sniper rifles that was developed by Dr. John D. Taylor and machinist William O. Wordman. It was designed with a possible military need in mind for a cartridge for both the anti-personnel, anti-sniper and anti-materiel role with a (supersonic) precision range of 2,187 yards (2,000 m). It is hoped it will fill in a supposed market niche as an intermediate between the existing military long-range cartridges .338 Lapua Magnum and the .50 BMG.