This replacement bolt for any of lwrc rifles chambered in 6.8mm, including both the six8 line and the legacy m6 rifles with 6.8 spc barrels.This bolt fits into any mil-std carrier and functions accordingly.With a fully supported bolt face, lwcr's acbs lack the two undercuts on either side of the extractor pocket that weaken traditional bolts.In addition, the extractor utilizes a dual-spring design that increases extraction force and triples the service life.Machined out of a super-alloy formulated to take extreme loads without failure, they are also shot-peened for extra durability.A nickel-boron coating increases strength and lowers the coefficient of friction.All of these factors and more make our six8 acb the best choice for any 6.8mm spc firearm.Finish: Nickel BoronType: BoltModel: Advanced CombatSize: 6.8 SPCMaterial: Aluminum