{"product_id":"cmmg-mk4-ar-15-upper-receiver-assembly-5-56-nato-14-5-1-7-armor-black","title":"CMMG Mk4 AR-15 Upper Receiver Assembly 5.56 NATO 14.5\" 1:7 Armor Black","description":"\u003cp\u003e\u003cspan style=\"font-size: 14pt;\"\u003eThe \u003cstrong\u003e\u003cspan style=\"background-color: #ffff00;\"\u003eCMMG Mk4 AR-15 Upper Receiver Assembly\u003c\/span\u003e\u003c\/strong\u003e is a complete, ready-to-install upper built around CMMG's signature enlarged-ejection-port design and chambered in \u003cstrong\u003e\u003cspan style=\"background-color: #ffff00;\"\u003e5.56 NATO\u003c\/span\u003e\u003c\/strong\u003e (also compatible with .223 Remington). The receiver is precision machined from \u003cstrong\u003e6061-T6 billet aircraft-grade aluminum\u003c\/strong\u003e and finished in CMMG's \u003cstrong\u003eArmor Black\u003c\/strong\u003e coating, giving it the same look and finish as the company's complete Mk4 rifles.\u003c\/span\u003e\u003c\/p\u003e\n\n\u003cp\u003e\u003cspan style=\"font-size: 14pt;\"\u003eAt the heart of this assembly is a \u003cstrong\u003e14.5\" steel barrel\u003c\/strong\u003e with a \u003cstrong\u003e1:7\" twist\u003c\/strong\u003e. The Mk4's \u003cstrong\u003eenlarged ejection port\u003c\/strong\u003e is engineered to clear a variety of alternate bolt-and-barrel conversions in \u003cstrong\u003e9mm, 10mm, .40 S\u0026amp;W, and .45 ACP\u003c\/strong\u003e, allowing this upper to serve as the foundation of a multi-caliber AR build.\u003c\/span\u003e\u003c\/p\u003e\n\n\u003cp\u003e\u003cspan style=\"font-size: 14pt;\"\u003eThis upper ships ready to drop onto any mil-spec AR-15 or Mk4 lower receiver and comes with CMMG's \u003cstrong\u003eZEROED polymer dust cover\u003c\/strong\u003e pre-installed.\u003c\/span\u003e\u003c\/p\u003e","brand":"CMMG","offers":[{"title":"Default Title","offer_id":55291426373954,"sku":"55BA290AB","price":125.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0997\/7921\/5682\/files\/alt_0999876a-e6ff-4e82-a2ea-6f25d128ce31.jpg?v=1785101444","url":"https:\/\/centerfiresystems.com\/products\/cmmg-mk4-ar-15-upper-receiver-assembly-5-56-nato-14-5-1-7-armor-black","provider":"Centerfire Systems","version":"1.0","type":"link"}