Ever since Alexander Arms’ 6.5mm Grendel and Remington’s 6.8mm Special Purpose Cartridge (SPC) were introduced during 2004, there is ongoing debate between some members of the shooting community as to which round would be the better choice to succeed 5.56mm NATO for military use.

This article will attempt to provide an objective evaluation as to whether the 6.5 Grendel or 6.8 SPC is the superior alternative by comparing the characteristics of each round and the measures necessary to utilize these cartridges in the M4 carbine, M16 squad marksman rifle, and M249 light machine gun.

The genesis of the two rounds could hardly have been more different. The 6.5 Grendel was conceived as a sporting cartridge and it was designed to give the civilian AR-15 owner the capability for precision shooting at long range. Load development centered on competition and hunting rounds, which remain the only types of factory ammunition currently marketed. However, the performance potential of 6.5 Grendel caused some enthusiasts to advocate it for use by the military and factory loadings that would be legal for combat use are slowly becoming available.

The birth of the 6.8 SPC was just the opposite, having been created as a combat cartridge for special operations, and developed specifically to provide the military M4 shooter enhanced terminal effects on enemy personnel at typical engagement distances. Because of this a significant percentage of 6.8 SPC development efforts by commercial firms has been devoted to loadings that would be lawful for land warfare, some of which have full metal jacket, armor piercing and hollowpoint match bullets.