The United States Special Operations Command (SOCOM) is considering a caliber change for their future semiautomatic sniper weapons systems. Although traditionally these medium range precision weapons have been chambered for the 7.62x51mm caliber common to NATO, it seems SOCOM is looking to get a little more out of them by changing over to a new 6.5mm/0.264″ caliber round. The Command is investigating two off-the-shelf options: The 6.5mm Creedmoor (6.5x49mm) and the .260 Remington (6.5x52mm). Both rounds are extremely similar, each being based on the .308 Winchester case (the Creedmoor by way of the all-but-forgotten .30 T/C) necked down. From Military Times:

Special Operations Command is exploring a new caliber for its semi-automatic sniper rifle needs and upgrading one of its bolt-action sniper rifle systems.

Maj. Aron Hauquitz told Military Times Tuesday that SOCOM is in the preliminary stages of exploring a sniper rifle chambered in the 6.5 mm caliber. The two commercially available rounds being evaluated are the .260 Remington and the 6.5 mm Creedmoor.

Research shows that both rounds will “stay supersonic longer, have less wind drift and better terminal performance than 7.62 mm ammunition,” SOCOM officials said.

Hauquitz said that the research is focused on the popularity and availability of the cartridge, and finding out the benefits and drawbacks of the different rounds.

…

He didn’t provide a specific date or timeline for when the new rifle would be in operators’ hands but said they would have a better idea regarding the caliber later this year.

“We’re purely in the exploratory phase,” Hauquitz said. “We’re trying to see if we can take a weapon that is 7.62 and give it greater range, accuracy and lethality.”

Hauquitz said the 6.5 mm exploration came out of preliminary results of the Small Arms Ammunition Configuration study, which evaluates for the military commercially available ammunition, emerging ammunition capabilities, and ammunition technologies for conventional and non-conventional calibers.

The primary differences between the 6.5 Creedmoor and the .260 Remington are the slightly shorter case and slightly longer neck of the Creedmoor, and the more aggressive shoulder and slightly greater case taper of the .260 Remington. Other than those differences (which make the two decidedly non-interchangeable), both rounds are essentially the same, providing very similar levels of performance. Versus the 7.62mm, either 6.5mm offers a much flatter trajectory, greater wind resistance, and shorter flight time; in these respects the hotshot 6.5s more resemble the .300 Winchester Magnum which has been used in military sniper rifles than they do the 7.62mm. In addition, both rounds give greater striking velocity and energy at extended distances, adding penetration and possibly also fragmentation range versus 7.62.

The new caliber will apparently be sought for the semiautomatic sniper system, as well as the Advanced Sniper Rifle (ASR), and an M40A6 upgrade.