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Sig P365 Fire Control Unit (FCU) – Build Your Custom Pistol
🔧 The Serialized Core of the Sig Sauer P365 Platform
The Sig P365 Fire Control Unit is the serialized, legally regulated heart of the P365 series. As the only part considered the actual “firearm,” this drop-in FCU gives you the foundation to build a completely custom P365, P365XL, or P365 XMacro to your exact specs.
Whether you're starting from scratch or replacing a stripped-down lower, this Sig factory fire control unit is ready to accept your choice of slide, grip module, trigger, and barrel — putting total control in your hands.
Key Features:
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✅ Serialized stainless steel chassis – Registered firearm component
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✅ Works with P365, P365XL, XMacro, and custom grip modules
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✅ Accepts both factory and aftermarket triggers
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✅ Drop-in compatibility with Sig OEM and custom slides
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✅ Factory-tested and ready for transfer through your FFL
💡 Why Buy a Standalone P365 FCU?
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Legal DIY Builds – Assemble a fully custom P365 from the ground up
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Ultimate Modularity – Use with any grip module or slide configuration
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Lower Cost Customization – Build only the gun you want — nothing extra
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Genuine Sig Sauer Quality – No clones, no compromises
🛒 Pair It With These Popular Upgrades:
🧠 FAQ: Sig P365 Fire Control Unit
Q: What exactly is the Sig P365 FCU?
A: The FCU is the serialized trigger chassis that houses the fire control group — it’s legally recognized as the firearm itself.
Q: Can I build a complete P365 using this FCU?
A: Yes. Once you receive it via FFL, you can build a custom P365, P365XL, or XMacro by selecting your own grip module, slide, and barrel.
Q: Is the FCU compatible with manual safety grip modules?
A: Yes. Be sure to purchase a grip module that matches your safety preference (manual safety or no-safety).
Q: Do I need an FFL to purchase this?
A: Yes. The FCU is a regulated firearm part and must ship to a licensed FFL dealer.
🚀 Why Buy From Mounts Plus?
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✔️ Genuine Sig Sauer factory parts
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✔️ Fast shipping to your preferred FFL
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✔️ Build support and upgrade compatibility
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✔️ Trusted by gun builders and pros across the country
🧰 Build the P365 You Really Want
The Sig Sauer P365 Fire Control Unit is your launchpad to complete pistol personalization. Whether you're upgrading from OEM or building from scratch, start with the foundation that gives you freedom — and factory-grade precision.
🛒 Order now and start your build today.