ST50 Conversion Kit Review: P90 5.7x28 Pistol Platform
ST50 Conversion Kit Review: P90 5.7x28 Pistol Platform. First look at the ST50, a Kel-Tec P50 conversion kit with AR-compatible fire control and 50-round P90 magazine capacity. Unique, range-fun build with modular { "@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/tactical_advisor#person", "name": "Tactical Advisor", "url": "https://greyhive.com/c/tactical_advisor", "description": "Tactical Advisor is a Greyhive creator producing original 2A, firearms, hunting, and outdoor content.", "image": "https://greyhive.com/lazy-static/avatars/dee0ba66-5df6-48e3-8291-b1698be128e8.jpg" }, { "@type": "Article", "@id": "https://greyhive.com/blog/st50-conversion-kit-p90-review#article", "isPartOf": { "@id": "https://greyhive.com#website" }, "mainEntityOfPage": { "@id": "https://greyhive.com/blog/st50-conversion-kit-p90-review" }, "url": "https://greyhive.com/blog/st50-conversion-kit-p90-review", "headline": "ST50 Conversion Kit Review: P90 5.7x28 Pistol Platform", "name": "ST50 Conversion Kit Review: P90 5.7x28 Pistol Platform", "description": "First look at the ST50, a Kel-Tec P50 conversion kit with AR-compatible fire control and 50-round P90 magazine capacity. Unique, range-fun build with modular", "articleSection": "Gun Reviews", "articleBody": "The ST50 conversion kit is Stuff & Things' take on the Kel-Tec P50 — you keep the top half (barrel and receiver), pull the factory back end, and bolt on a modular fire control group that runs standard AR-15 parts. In his first-look review on Greyhive, Chris from Tactical Advisor called it \"one of the most unique guns I've ever shot,\" and the pitch is simple: P90-pattern 5.7x28 firepower on a platform you can build with the AR trigger, grip, and safety selector you already own. Think of it as the Kel-Tec P50 \"minus the P\" — the ST50. Where the stock P50 comes locked into its own fire control, the ST50 opens that back half up to the entire AR parts ecosystem. Buy it complete with a trigger, safety, and grip installed, or grab it stripped to save money and drop in your own favorites. What makes the ST50 genuinely notable isn't just the parts compatibility — it's that Tactical Advisor's full look at the FRT-equipped version got age-restricted, demonetized, and outright blocked on YouTube, despite the trigger being a completely legal, ship-to-your-door semi-automatic. That's exactly the kind of content that lives uncensored on Greyhive. Key Takeaways The ST50 is a Stuff & Things conversion of the Kel-Tec P50 — keep the top/barrel, swap the rear fire control group. Runs standard AR-15 trigger, safety selector, and grip; available complete or stripped for a custom build. Feeds from double-coupl…