{"product_id":"spikes-m4-upper-forged-ft-multical","title":"Spike's Tactical M4 Forged Upper Receiver – Multi-Caliber Flat-Top AR-15","description":"\u003cp\u003eThe Spike's Tactical M4 Forged Upper Receiver is a multi-caliber flat-top platform compatible with standard AR-15 lower receivers. Designed for 5.56 NATO\/.223 Remington and other AR-15 pattern calibers, this stripped upper provides a mil-spec foundation for custom builds. The continuous Picatinny rail allows unlimited optic and sight configurations.\u003c\/p\u003e\u003cp\u003eMachined from 7075-T6 forged aluminum with a hard coat anodized finish for durability and corrosion resistance. This is a stripped upper receiver with ejection port cover and forward assist installed—no barrel, handguard, or bolt carrier group included. Accepts standard AR-15 barrel nuts and handguards. Requires basic armorer tools and knowledge of AR-15 assembly for installation.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCaliber:\u003c\/strong\u003e Multi-caliber (5.56 NATO, .223 Remington, and other AR-15 compatible calibers)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eType:\u003c\/strong\u003e Forged stripped upper receiver\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompatible Lower:\u003c\/strong\u003e AR-15 \/ M4 lower receivers\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e 7075-T6 forged aluminum\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFinish:\u003c\/strong\u003e Hard coat anodized\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIncludes:\u003c\/strong\u003e Ejection port cover and forward assist installed\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstallation:\u003c\/strong\u003e Requires barrel, bolt carrier group, charging handle, and handguard (sold separately)\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Spike's Tactical","offers":[{"title":"Default Title","offer_id":47938903376127,"sku":"SPKSFT50M4","price":106.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0729\/0434\/3807\/files\/1336202.jpg?v=1766535911","url":"https:\/\/doublestackstore.com\/products\/spikes-m4-upper-forged-ft-multical","provider":"Double Stack Store","version":"1.0","type":"link"}