Starline 6mm Creedmoor Large Pocket Brass Cases 100ct Starline Brass 6mm Creedmoor (Large Rifle primer) 1.908 - 1.912 O.A.L. The 6mm Creedmoor is the little brother to the very popular 6.5 Creedmoor. It has similar ballistics to the .243 Winchester, but its shorter length allows long, heavy bullets to be seated in the magazine. This caliber is an excellent choice for hunting, but its popularity was gained as a competition cartridge. Some of the new competitions, such as the Precision Rifle Series, require a lot of shooting and this cartridge is easy on the shoulder, even compared to the 6.5 Creedmoor. There are several companies now making bolt action and AR-10 type rifles for this caliber. 100 count by weight