BCA's Bolt carrier groups are MPI inspected. This ar 15 bolt carrier group (BCG) works with ar-15 calibers .223 Wylde, 5.56 NATO, .300 Blackout, and .350 Legend. it is right side charging. Specifications: Brand: Bear Creek ArsenalCaliber / Gauge: .223 Wylde/5.56 Nato/.300 BLK/.350 LegendCarrier Style: Side ChargingPlatform: AR-15 Bolt Finish: ParkerizedBolt Material: 9310 Steel Carrier Finish: Black NitrideGas Key: Staked from the side to increase longevity Magnetic Particle Inspection: Yes Comes with side charging handle & screw {{widget type="Magento\Cms\Block\Widget\Block" template="widget/static_block/default.phtml" block_id="42"}}