sentences:  The bullet was designed using some NACA low-supersonic-drag equations to design the shape.The cartridge was designed as an improvement to the .50 BMG cartridge, a common machine gun and rifle cartridge.It is a wildcatted .50 BMG case, shortened to from its original length of 3.91 inches (99 mm) and necked down to accept a .416 caliber, projectile; however, the case dimensions are proprietary.