The 6.8mm Remington SPC was designed to perform better in short barreled AR 15 rifles after diminished performance from the 5.56 NATO. The 6.8 SPC delivers 44% more energy than the 5.56mm NATO at 330 to 980 ft. The 6.8 SPC is a robust little round that can be used for a variety of different tasks. The 6.8 SPC is a surprisingly popular hunting cartridge. Its been a popular alternative for AR hunters in states that prohibit the 5.56/223 as a hunting round. It also offers a little more oomph and power for more massive game as well.