The 6mm Creedmoor is a relatively new and popular cartridge for long-range shooting. It was developed in 2007 by Hornady Manufacturing Company, a well-known ammunition manufacturer in the United States. The cartridge is based on the .30 Thompson/Center cartridge case, but with modifications to the shoulder angle and the neck length. It is a centerfire cartridge, which means that the primer is located in the center of the base of the cartridge case. The 6mm Creedmoor uses a .243-inch diameter bullet, which is smaller than the .308-inch diameter bullet commonly used in other long-range cartridges. This smaller bullet allows for a higher velocity and a flatter trajectory, making it a popular choice for long-range target shooting and hunting.

The 6mm Creedmoor has gained popularity in recent years due to its accuracy and versatility. It has a reputation for being very consistent, which is important for long-range shooting where small variations in bullet trajectory can make a big difference. The cartridge also has relatively low recoil, making it easier to shoot accurately over long distances. The 6mm Creedmoor has been used in competitive shooting, such as in the Precision Rifle Series, as well as in hunting, particularly for small to medium-sized game. It has become a popular choice among long-range shooters, and its popularity is expected to continue to grow in the coming years.