{"product_id":"wmd-upper-assy-300blk-16-barrel","title":"WMD Guns 300 Blackout Complete Upper Assembly – 16\" Barrel, AR-15 Platform","description":"\u003cp\u003eThe WMD Guns 300 Blackout Complete Upper Assembly delivers reliable performance in a versatile chambering suited for both subsonic and supersonic applications. Built for standard AR-15 lowers, this 16-inch upper configuration provides the ballistic efficiency 300 BLK is known for while maintaining legal compliance for rifle-length firearms. The 16-inch barrel optimizes velocity for supersonic loads while still functioning effectively with subsonic ammunition when paired with a suppressor.\u003c\/p\u003e\u003cp\u003eWMD Guns applies their proprietary NiB-X nickel boron coating to critical components, offering enhanced corrosion resistance and reduced friction compared to standard phosphate finishes. This complete upper assembly arrives ready to install on any mil-spec AR-15 lower receiver. Confirm headspace and function-test with your specific lower and bolt carrier group before live fire. As with any 300 Blackout firearm, exercise strict ammunition discipline—chambering 300 BLK in a 5.56 upper or vice versa can cause catastrophic failure.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCaliber:\u003c\/strong\u003e 300 Blackout\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eType:\u003c\/strong\u003e Complete Upper Assembly\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompatible Lower:\u003c\/strong\u003e AR-15 (mil-spec)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBarrel Length:\u003c\/strong\u003e 16 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Forged aluminum receiver, steel barrel\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFinish:\u003c\/strong\u003e NiB-X nickel boron coating on key components\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIncludes:\u003c\/strong\u003e Upper receiver, barrel, handguard, gas system, charging handle (confirm specific components with manufacturer)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstallation:\u003c\/strong\u003e Attaches to mil-spec AR-15 lower; verify headspace before use\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"WMD Guns","offers":[{"title":"Default Title","offer_id":47939839230207,"sku":"WMDNIBXUA300BO-16","price":607.95,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0729\/0434\/3807\/files\/5594881.jpg?v=1766548452","url":"https:\/\/doublestackstore.com\/products\/wmd-upper-assy-300blk-16-barrel","provider":"Double Stack Store","version":"1.0","type":"link"}