#7x46mm
7x46mm UIAC (Universal Intermediate Assault Cartridge)
Cris E. Murray helped design the 6.8mm SPC cartridge for SOCOM and considers it to be the best cartridge for the AR-15 platform and similarly sized weapons. The problem with the 6.8mm SPC, and similar cartridges like the 6.5mm Grendel, is that their performance has been constrained by the necessity of the cartridge to be able to be chambered in a M16 or M4.
