Mercury Precision LR-308 Complete Bolt Carrier Assembly Nickel Boron Finish - .308 WIN/6.5 Creedmoor/.243 WIN

An LR-308 / AR-10 bolt carrier group is a piece of a firearm that houses many important parts such as the firing pin, gas key, cam pin, extractor, and bolt. With all these pieces working together the BCG can grab and feed another round out of a detachable magazine, chambers and engages the cam groove, engage with the locking lugs in the barrel, fire, and extract a spent cartridge. During the extraction of a cartridge, the BCG works to absorb the force of the explosion by expanding gas in the carrier. During this process gas is tapped off from the barrel and is sent into the cup inside of the gas key, creating an inertial force that sends the Bolt Carrier Group back into the buffer tube which helps to minimize the recoil of your gun when firing and the cycle will repeat for subsequent shots.

About this BCG: This BCG is an AR-10 / LR-308 compatible design, allowing use with .308 Winchester, 7.62 NATO, 6.5 Creedmooor, & .243 Win cartridges. The standard AR-10 / LR-308 bolt carrier is also machined from 9310/8620 Alloy Steel and is completed with a Nitride finish. This BCG comes with the ability to be full-auto compatible and also features forward assist notches. MPI testing has also been done to ensure that there are no structural flaws to this BCG.

Caliber Compatibility: .308 Win, 7.62 NATO, 6.5 Creedmoor, .243 Win - This BCG is standard for the .308 Win, 7.62 NATO, 6.5 Creedmoor, .243 Win calibers, and is interchangeable between all 4 simultaneously.

Finish: Nickel Boron - Nickel Barrel Bolt Carrier Groups are popular for their incredible strength and reliability under minimal or zero lubrication.

Material: 9310 Alloy Steel - Bolt Head - 9310 Steel is a low alloy steel that is a mixture of nickel, chromium, and molybdenum. This steel is built to have high core hardness and high fatigue strength which make it the perfect steel to hold up in the harsh environments of the bolt head.

8620 Alloy Steel - Body - 8620 Steel is a carburized alloy steel meaning carbon was added to increase hardness of the steel. 8620 is known for its high case toughness and high core toughness. Made mostly of nickel concentrate, this steel can easily withstand the firing stress of the BCG under operation.

Forward Assist Notches: This BCG comes with forward assist notches which allow the forward assist on the upper to contact the BCG pushing it forward and locking the bolt into place. These forward assist notches can also help clear malfunctions in a speedy manner when the BCG becomes jammed.

Gas System: Direct Impingement - Direct impingement is the process of directing the gas created during the operation of a firearm through the barrel, gas block, gas tube, and eventually into the BCG again to cycle the action and prepare the firearm for another round.

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Warranty, Returns & Terms: MMC Armory offers a 30 day return, refund and exchange policy. You must email/call MMC Armory and obtain an RMA number prior to any return, refund, or exchange. All returns must include the original order number, receipt or invoice, along with the billing address, shipping address, contact phone numbers, contact emails, and RMA number. Returns, refunds, and exchanges may take up to two weeks, not including transit times, for processing after we receive it. Return shipping costs will be the responsibility of the returning party, with the exception of the wrong item being received or on warranty exchange during the first 30 days after delivery. Items returned for warranty will only be replaced or exchanged, not refunded.