United Defense AR-15 5.56/.223/.300/.350
Complete Bolt Carrier Group
*Made In The USA*
*Limit 1 Per Order*
An AR-15 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-15 compatible design, allowing use with .223 Remington, 5.56 NATO, .300 Blackout, & .350 Legend cartridges. The standard AR-15 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 fully-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: .223 Rem, 5.56 NATO, .300 BLK, .350 Legend - This BCG is standard for the .223 Rem, 5.56 NATO, .300 Blackout, .350 LGND calibers, and is interchangeable between all 4 simultaneously. This includes .22 Nosler Chambered AR-15s and .223 Wylde rifles.
Finish: Nitride - Nitriding is a process during manufacturing that diffuses nitrogen into the steel to make a case-hardened surface for improved resistance and strength. A Nitrided BCG typically has a gloss black texture. Nitrided Bolt Carriers have increased resistance from heat, and corrosion.
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 the 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.
Brand: United Defense
Caliber Compatibility: 5.56 NATO, .223 Rem, .300 BLK, .350 Legend
Bolt Head Material: 9310 Alloy Steel
Bolt Head Finish: Nitride
Body Material: 8620 Alloy Steel
Body Finish: Nitride
Gas System: Direct Impingement
Forward Assist Cuts: Yes
Full Auto Compatible: Yes