CMMG 55BA419 Bolt Carrier Group 5.56x45mm NATO Black Steel M16
https://www.tandktactical.com/shop/852005002431-cmmg-55ba419-bolt-carrier-group-5-56x45mm-nato-black-steel-m16-13323
https://www.tandktactical.com/web/image/product.template/13323/image_1920?unique=e851535
Complete Mil-Spec M16 bolt carrier group.
