{"product_id":"cmmg-57d0476-replacement-barrel-kit-w-bcg-5-7x28mm-16-1-threaded-black-salt-bath-nitride","title":"CMMG 57D0476 Replacement Barrel Kit w\/ BCG 5.7x28mm 16.1\" Threaded - Black Salt Bath Nitride","description":"\u003cp\u003e\u003cspan style=\"font-size: 14pt;\"\u003eThe \u003cstrong\u003e\u003cspan style=\"background-color: #ffff00;\"\u003eCMMG 57D0476\u003c\/span\u003e\u003c\/strong\u003e is a complete \u003cstrong\u003e5.7x28mm\u003c\/strong\u003e \u003cstrong\u003ebarrel and bolt carrier group kit\u003c\/strong\u003e built for the AR-platform. Designed to drop into a \u003cstrong\u003eMk4 \/ Mil-Spec AR-15 upper receiver\u003c\/strong\u003e, this kit lets a shooter build or convert an AR-platform firearm to the high-velocity 5.7x28mm cartridge using a CMMG Mk57 lower receiver or any standard Mk4 \/ AR-15 Mil-Spec lower when paired with CMMG 5.7 AR Conversion Magazines.\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan style=\"font-size: 14pt;\"\u003eThe barrel is a \u003cstrong\u003e16.10\" threaded\u003c\/strong\u003e profile cut from \u003cstrong\u003e4140 Chrome Moly steel\u003c\/strong\u003e and finished in \u003cstrong\u003e\u003cspan style=\"background-color: #ffff00;\"\u003eSalt Bath Nitride\u003c\/span\u003e\u003c\/strong\u003e for a durable, corrosion-resistant matte black surface. The matched bolt carrier group uses CMMG's signature \u003cstrong\u003eRadial Delayed Blowback\u003c\/strong\u003e operating system, purpose-engineered to safely handle the high pressures of the 5.7x28mm cartridge in an AR-platform format.\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan style=\"font-size: 14pt;\"\u003eThis is a genuine CMMG replacement and build component - the barrel and BCG are sold together as a matched set and are intended to be assembled into a host upper receiver. Whether you are building a new 5.7x28mm AR from the ground up or converting an existing lower, the 57D0476 kit provides the critical operating components in one package.\u003c\/span\u003e\u003c\/p\u003e","brand":"CMMG","offers":[{"title":"Default Title","offer_id":55112364654914,"sku":"158966","price":443.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0997\/7921\/5682\/files\/hires_4e197f5b-abdf-432d-b3e1-9c142b3e061d.png?v=1784806020","url":"https:\/\/centerfiresystems.com\/products\/cmmg-57d0476-replacement-barrel-kit-w-bcg-5-7x28mm-16-1-threaded-black-salt-bath-nitride","provider":"Centerfire Systems","version":"1.0","type":"link"}