The 6.8 SPC rifle (above) provides nearly identical trajectory as the 5.56 (below), but offers superior terminal performance in the same package with little extra recoil.
Numerous articles and Internet rumors have suggested that the SPC designation means 6.8 is good only for Close Quarters Battle (CQB), but not distant targets. This is incorrect, and contrary to the intent of the project and capabilities of the cartridge.
In open country where targets often appear beyond 200 yards, 6.8 SPC extends the shooter's ballistic advantage and delivers more power on target than 5.56.
Based on their experience with 7.62x39mm, the project team set a velocity goal of 200fps faster than the AK-47 ammunition from the same barrel length, with a projectile that provided a better ballistic coefficient (BC) and terminal performance. This was achieved very soon into the project using Sierra 115-grain and Hornady 110-grain Open-Tip Match (OTM) bullets. Using Ramshot 1660 powder for initial development, the team easily exceeded the 200fps goal. Shooting from an 18-inch SPR barrel, these loads shot 2635 to 2650fps, 300fps faster than the AK-47.
Unlike military-industrial-complex programs such as the XM-8, the ERC project was driven directly by Special Forces shooters at the spear's tip-- men who had been on the giving and receiving ends of fire. The 6.8 SPC was developed with less than $5,000 initial investment of government funds; later development costs were paid for by industry. This is in stark contrast to top-down "next generation" programs costing the tax-payers millions and rarely producing usable weapons systems.