The new 6.8mm rifle round developed for SOCOM (Special Operations Command), will be available commercially later this year as the 6.8mm Remington SPC (Special Purpose Cartridge). The manufacturer says the round wont be available to the public until the middle of the year, because of the need to produce sufficient quantities of the round for military contracts. There have been some problems in manufacturing the 6.8mm SPC. Remington began work on the new round in 2002. It used the case from the old Remington .30-.30 (which was not a true .30-.30, as it was rimless.) SOCOM has been testing the 6.8mm round in M-16s and M-4s modified to accommodate it. The 6.8mm round is more accurate at longer ranges and has more hitting power than the 5.56mm round the M-16 was originally designed for. Out to about 600 meters, the 6.8mm round has about the same impact as the heavier 7.62mm round used in sniper rifles and medium machine-guns.
During the 1930s, the Germans studied their World War I experience and concluded that a less powerful and lighter rifle round would be more effective. This resulted in research on a smaller 7mm round, but with World War II fast approaching, this effort eventually produced a shortened regular (7.92mm) rifle round. During that war, the Germans developed the first modern assault rifle, the SG-44. This weapon looked a lot like the AK-47, and that was no accident. The SG-44, like the AK-47, used a shortened rifle cartridge that was developed before the war (7.92mm for the Germans, 7.62mm for the Russians, which is still used in the AK-47). This gave the infantryman an automatic weapon that could still fire fairly accurate shots at targets 100-200 meters away. The SG-44, and the AK-47, had about the same stopping power as the 6.8mm SPC at those shorter ranges. What a coincidence. The AK-47 didn't have the accuracy of higher powered bullets, but the Russians didn't see this as a problem, because most troops using it had little marksmanship training. If they had to kill someone, they could fire at full auto. The U.S. M-16, and its high speed 5.56mm round, was more accurate than the AK-47 when firing individual shots at shorter ranges. But the wounding power of the 5.56mm (.22 caliber) bullet fell off rapidly at ranges over a hundred meters. The American military, and especially SOCOM, train their troops to fire individual shots, and do it with great accuracy at any range. A number of new rifle sights have made even easier to do, and makes first round hits at longer ranges easier to make. This made the longer range shortcomings of the 5.56mm round more obvious.
SOCOM has been using the 6.8mm round in Iraq and Afghanistan, and the users like it. But there is resistance from senior (non-SOCOM) generals to any consideration for replacing the 5.56mm round with the 6.8mm. To further complicate matters, theres a new 6.5mm Grendel round being tested as well, and some troops prefer it to the 6.8mm SPC. This is because the 6.5mm round is more accurate than the 6.8mm one at ranges beyond 500 meters. At the moment, no decision has been made about any replacement for the 5.56mm round.