First of all, what’s a 6.8 Remington SPC?
While at first glance it may look like a 5.56mm round, it’s not. Mainly because it’s bigger in all ways. Some folks from the U.S. Army Marksmanship Unit, United States Special Operations Command and Remington got together to work up a new cartridge that maintained reasonable compatibility with the AR platform, yet offered improved terminal ballistics and effective range.
The 6.8 Remington SPC is made from a shortened and necked-down .30 Remington cartridge case. The shortened part is to maintain compatibility with the magazine size of the existing AR platform. According to The folks at Sierra Bullets, “With the magazine length of the AR at 2.260″, cartridge length was critical. There are now magazines on the market designed specifically for the 6.8 mm SPC to allow them to be loaded out to 2.315.”
The projectile itself is a 7.035mm. Actually, you have heard of that because it’s a standard .270 size, which really means that the bullet measures .277 inches in diameter. Why do we make caliber stuff so cryptic? The projectile size is important as .270 bullets are widely available. Bullet weight of “average” 6.8 Remington SPC loads range from 90 to 120 grains or so, with most factory ammo having 90, 110, or 115 grain bullet weight.