Emary selected 6.5 mm for the new round because of the available selection of 0.264-inch-diameter match projectiles, all of which offer high ballistic coefficients and excellent accuracy. It also didn't hurt that one of the very best of those projectiles-the 140-gr. A-MAX (0.550 BC)-was already made by Hornady.
The new cartridge, named 6.5 Creedmoor in recognition of DeMille's contribution, commenced production in June 2008 with Hornady's new 120-gr. A-MAX bullet (0.465 BC). The 140-gr. A-MAX load was released in volume about a month later.
The 6.5 Creedmoor could be described as a .260 Rem. modified with a 0.11-inch shorter case, a sharper 30-degree shoulder, and less body taper. Full case capacity of the Creedmoor is 52.1 grs. of water, compared to 54.4 grs. for the .260 Rem. (both measurements taken using new, unfired cases). When match bullets are seated to 2.800-inch overall length (OAL) in both cartridges, however, the deeper bullet intrusion into the Remington case reduces the difference in effective capacity to only about 0.7 gr.
Current specifications for the 120-gr. A-MAX load are 44.5 grs. of H4350 powder, a Fed. 210M primer and 2.720-inch OAL for 3020 f.p.s. muzzle velocity. For the 140-gr. A-MAX, they are 41.9 grs. of H4350, a Fed. 210M primer and 2.80-inch OAL for a muzzle velocity of 2820 f.p.s. Velocities were measured in 28-inch barrels. The OAL of the 120-gr. load is shorter than that of its 140-gr. sibling to accommodate the lighter bullet's fatter ogive, which requires deeper seating in the case to prevent contact with the rifling.