Developed by Master Sergeant Steve Holland and Chris Murray, for consideration as a superior battlefield chambering for the AR-15 platform, Remington standardized the 6.8 Spc in 2002. It derives from the 30 Remington rimless case. I happen to own a bunch of cases worked with while they were developing this round — sometimes it is a small world. They shortened the case, established an appropriate body taper, set a good shoulder angle, and figured out a reasonable neck length. Then they set about to establish a safe and dependable maximum-working-pressure for this 27-caliber cartridge when used in the AR-15 platform. This proved to be 55,000 psi, compared to the 64,000 psi for the 5.56 NATO. Despite the necessarily lower working pressure, compared to the 5.56, the 6.8 can generate 15% more muzzle energy and deliver much greater energy at extended distances. It does exactly what the designers envisioned but it never gained the acceptance they hoped to see. The 6.8 is perhaps most interesting for being one of a very short list of 27-caliber cartridges ever standardized; following the 270 Winchester which followed the 6.8mm Chinese Mauser, the 6.8 Spc was standardized the same year as the 270 Winchester Short Magnum. The 6.8 Spc is the immediate progenitor of the 22 Valkyrie. In days hence, that might well be the only reason it is remembered, time will tell.