An AR-15 bolt carrier group is the critical piece of an upper receiver 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. For .224 Valkyrie / 6.8 SPC bolt carriers, the bolt head is larger to accept the larger diameter casing of .224 Valkyrie / 6.8 SPC Cartridges.
About this BCG: This BCG is an AR-15 compatible design, allowing use with .224 Valkyrie & 6.8 SPC cartridges. The .224 Valkyrie & 6.8 SPC AR-15 bolt carrier is also machined from 158 Carpenter Steel and is completed with a Phosphate 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 Compatability: .224 Valkyrie / 6.8 SPC - This BCG is designed for use with .224 Valkyrie and 6.8SPC cartridges. .224 Valkyrie was designed to offer greater accuracy and energy delivery at long range with a .22 caliber projectile. 6.8 SPC was an experimental intermediate rifle cartridge designed to fill the gaps between 5.56 NATO and 7.62 NATO rifle rounds.
Finish: Manganese Phosphate - Manganese Phosphate finishes are used on Bolt Carriers to protect against corrosion and wear. Manganese Phosphate finish is considered for its toughness, and is used in multiple different applications such as aerospace, ordnance, and other firearms-related parts.
Material: 158 Carpenter Steel - Bolt Head - Body - 158 Carpenter Steel is Case Hardened on the outside to prevent wear and crack formation while the inside is softer and more flexible to prevent crack propagation and absorb shock loads.
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.
Brand: ADK Defense
Caliber Compatibility: 6.8 SPC, .224 Valkyrie
Bolt Head Material: 158 Carpenter Steel
Bolt Head Finish: Phosphate
Body Material: 158 Carpenter Steel
Body Finish: Phosphate
Gas System: Direct Impingement
Forward Assist Cuts: Yes
Full Auto Compatible: Yes
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Warranty, Returns & Terms: MMC Armory offers a 30 day return, refund and exchange policy. You must email or 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.