The new sniper bullet offers greater range than existing rounds, while the new machine gun round will be the foundation of a new, better weapon.
U.S. Army and special forces units are set to introduce two new small arms rounds in the near future meant to improve the effectiveness of troops in the field. Special operations snipers will replace their 7.62 bullets with a new round favored by civilian precision rifle shooters, while the Army’s next-generation squad machine gun will be chambered in a new caliber using new casing technology. The result will be snipers that can engage targets farther and machine guns that are more accurate and lethal than existing weapons.
On the sniper rifle front, according to Army Times, U.S. Special Operations Command is switching from the current 7.62×51-millimeter round—also known as .308 Winchester—to the relatively new 6.5-millimeter Creedmoor round. Introduced by ammunition maker Hornady in 2007, the round caught on with commercial precision rifle shooters due to superior long range ballistic performance over the 7.62×51 round.
As this article in NRA Shooting Illustrated demonstrates, the 6.5 Creedmoor travels at a higher velocity than the 7.62. At 1,000 yards, a 6.5 Creedmoor round requires less correction for bullet drop (gravity) and for wind than the 7.62 round. This reduces the margin for error for long range shots, especially when calculating the effects of wind.
Velocity is also important in another sense: bullets slowing from supersonic to subsonic speeds begin to act unpredictably, so it’s important to have a round with as high velocity as possible. At 1,000 yards, the 6.5 round will arrive at its target still traveling at 1,400 feet per second, well above the speed of sound, while the 7.62 round will arrive at 1,150 feet per second, “just past the cusp of the transonic window”.
The new 6.5 Creedmoor round is fairly easy to adopt on existing rifles—typically, 7.62-millimeter rifles just require a barrel swap to take advantage of the new round. The updated sniper rifles should also be externally identical to non-updated rifles, and magazines will hold the same number of rounds.