{"product_id":"rosco-556nato-300blk-bcg-melonite-bk","title":"Rosco Manufacturing 5.56 NATO\/300 BLK BCG Melonite Black – AR-15 Bolt Carrier Group","description":"\u003cp\u003eThe Rosco Manufacturing 5.56 NATO\/300 BLK Bolt Carrier Group is a mil-spec replacement or upgrade BCG designed for reliable cycling in AR-15 platforms chambered in 5.56 NATO or 300 Blackout. This BCG handles the core functions of extraction, ejection, and chambering—critical to consistent performance whether you're running supersonic 5.56 or subsonic 300 BLK loads. Shooters replace factory BCGs to improve reliability, reduce fouling buildup, or maintain a spare for training and competition use.\u003c\/p\u003e\u003cp\u003eConstructed from 8620 steel with a Melonite finish, this carrier group offers corrosion resistance and reduced friction for smoother operation and easier cleaning. The Melonite treatment penetrates the steel rather than coating the surface, providing long-term durability under high round counts. This is a drop-in part compatible with mil-spec AR-15 upper receivers—no gunsmithing required for installation.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Type:\u003c\/strong\u003e Bolt Carrier Group\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompatible Firearms:\u003c\/strong\u003e AR-15 chambered in 5.56 NATO, .223 Remington, 300 Blackout\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e 8620 Steel\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFinish:\u003c\/strong\u003e Melonite (Black)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstallation:\u003c\/strong\u003e Drop-In\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIncludes:\u003c\/strong\u003e Bolt Carrier Group Assembly\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Rosco Manufacturing","offers":[{"title":"Default Title","offer_id":47939680502015,"sku":"ROS-BCG-001","price":146.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0729\/0434\/3807\/files\/2979836.jpg?v=1766545669","url":"https:\/\/doublestackstore.com\/products\/rosco-556nato-300blk-bcg-melonite-bk","provider":"Double Stack Store","version":"1.0","type":"link"}