{"product_id":"solgw-m4-exo3-13-7-5-56-urg","title":"Sons of Liberty Gun Works M4-EXO3 13.7\" 5.56 NATO Upper Receiver Group – Mil-Spec AR-15","description":"\u003cp\u003eThe SOLGW M4-EXO3 13.7\" upper receiver group delivers a compact, pinned-and-welded configuration in 5.56 NATO, optimized for close-to-mid-range engagements. This complete upper fits mil-spec AR-15 lower receivers and features a 13.7\" barrel with a permanently attached muzzle device to meet the 16\" legal minimum, eliminating NFA registration requirements while maintaining a reduced overall length. The EXO3 rail system provides M-LOK attachment points and a low-profile design that balances weight savings with rigidity.\u003c\/p\u003e\u003cp\u003eBuilt with a forged 7075-T6 aluminum upper receiver and a chrome-moly-vanadium barrel with a carbine-length gas system, this upper is finished in a durable black anodized coating. The assembly includes a bolt carrier group and charging handle, ready to install on your lower receiver. No additional compliance work required—install, zero, and run.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCaliber:\u003c\/strong\u003e 5.56 NATO\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eType:\u003c\/strong\u003e Complete Upper Receiver Group\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompatible Lower:\u003c\/strong\u003e Mil-Spec AR-15\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBarrel Length:\u003c\/strong\u003e 13.7\" (pinned and welded to 16\")\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Forged 7075-T6 aluminum receiver, chrome-moly-vanadium barrel\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFinish:\u003c\/strong\u003e Black anodized\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIncludes:\u003c\/strong\u003e Bolt carrier group, charging handle, EXO3 M-LOK handguard\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstallation:\u003c\/strong\u003e Drop-in fit for mil-spec AR-15 lowers\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Sons of Liberty Gun Works","offers":[{"title":"Default Title","offer_id":47938879422719,"sku":"SOLGWEXO3UPPER-137-556","price":850.95,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0729\/0434\/3807\/files\/2876589.jpg?v=1766535103","url":"https:\/\/doublestackstore.com\/products\/solgw-m4-exo3-13-7-5-56-urg","provider":"Double Stack Store","version":"1.0","type":"link"}