Ops-Core Lockdown Liner Install: FAST Helmet Retrofit
Ops-Core Lockdown Liner Install: FAST Helmet Retrofit. Step-by-step install of the Ops-Core Lockdown Liner retrofit kit on legacy FAST helmets. Tools, fitment, and what changes vs the OEM liner. { "@context": "https://schema.org", "@graph": [ { "@type": "Organization", "@id": "https://greyhive.com#organization", "name": "Greyhive", "url": "https://greyhive.com", "description": "Greyhive is a censorship-resistant video platform for the firearms, 2A, hunting, and outdoor industries — where creators build, review, and monetize unfiltered content.", "logo": { "@type": "ImageObject", "url": "https://greyhive.com/static/uploads/images/ae198483-01c9-44b4-a16a-03f516ceaf66.svg", "width": 512, "height": 512 }, "sameAs": [ "https://x.com/greyhive", "https://www.instagram.com/greyhive/", "https://www.youtube.com/@Greyhive", "https://www.linkedin.com/company/greyhive/" ] }, { "@type": "WebSite", "@id": "https://greyhive.com#website", "url": "https://greyhive.com", "name": "Greyhive", "description": "Greyhive is a censorship-resistant video platform for the firearms, 2A, hunting, and outdoor industries — where creators build, review, and monetize unfiltered content.", "publisher": { "@id": "https://greyhive.com#organization" } }, { "@type": "Person", "@id": "https://greyhive.com/c/thin_line_defense_co#person", "name": "Thin Line Defense Co", "url": "https://greyhive.com/c/thin_line_defense_co", "description": "Thin Line Defense Co is a Greyhive creator producing original 2A, firearms, hunting, and outdoor content.", "image": "https://greyhive.com/lazy-static/avatars/f5dc0690-118d-4839-98e4-bb2b99960c0b.png" }, { "@type": "Article", "@id": "https://greyhive.com/blog/ops-core-lockdown-liner-retrofit-install-guide#article", "isPartOf": { "@id": "https://greyhive.com#website" }, "mainEntityOfPage": { "@id": "https://greyhive.com/blog/ops-core-lockdown-liner-retrofit-install-guide" }, "url": "https://greyhive.com/blog/ops-core-lockdown-liner-retrofit-install-guide", "headline": "How to Install Ops-Core Lockdown Liner Retrofit on FAST Helmets", "name": "How to Install Ops-Core Lockdown Liner Retrofit on FAST Helmets", "description": "Step-by-step walkthrough installing the Ops-Core Lockdown Liner upgrade kit to retrofit legacy FAST helmets with next-gen pad system, retention, and chin strap.", "articleSection": "Gear & Apparel", "articleBody": "The Ops-Core Lockdown Liner retrofit kit lets you upgrade any legacy FAST helmet — SF, XP, Maritime, Carbon — to the same pad system, chin strap, and rear retention found in the next-gen Ops-Core helmets. In his full walkthrough on Greyhive, Chris from Thin Line Defense Co tears a legacy SF helmet down to the shell and rebuilds it with the Lockdown Liner kit, showing every step from coin placement to final shim adjustment. The retrofit replaces the old skateboard-style foam liner with a modular pad system, swaps in the Lockdown Flex chin strap (runnable split or sled), and adds a low-sitting rear nape pad with an integrated retention dial. The result: better counterweight balance for night vision, no more aftermarket pad-and-retention Frankenbuilds, and a head fit you can dial in with included shims. This guide follows Chris's process step-by-step so you can retrofit your own FAST. One important note up front from the video: the Lockdown Liner kit works on the entire Ops-Core FAST family, but not on CH or ECH helmets — those need the separate Ops-Core LX9 liner system instead. Key Takeaways The Lockdown Liner kit retrofits any FAST helmet (SF, XP, legacy) — but not CH or ECH, which need the LX9 system. Full teardown to the shell is required, making it the perfect time to also install Power Path rails if y…