How to Assemble a Modular Firearm in the UK – Step-by-Step Guide
Thinking about building your own modular firearm in the UK? Whether for private use, legal collecting, or personal education, the demand for DIY gun kits is growing. In this article, we’ll show you how to safely and discreetly assemble a modular firearm kit, using legally sourced parts.
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What You Need to Begin
Before you begin assembly, you’ll need the following components, available at TopBoyGhostGuns.uk:
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A lower receiver/frame (3D printed or polymer)
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Upper assembly (slide, barrel, rails)
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Trigger group, pins & springs
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Magazine and grip modules
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Optional: jig kit, drill press, or finishing tools
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Printed instructions or video tutorial (included in select kits)
Check our full collection of ghost gun parts for sale in the UK to complete your setup.
Step-by-Step Assembly Process
Step 1: Prepare Your Workspace
Choose a clean, flat, private surface. You’ll need basic tools: small screwdriver, hex wrench, hammer, and possibly a vice. Be sure to work somewhere discreet.
Step 2: Install the Lower Internals
Take your 3D printed frame and begin installing the trigger, sear, safety selector, and pins. Ensure everything clicks or locks into place without forcing.
Get your UK-ready 3D printed gun kit here
Step 3: Attach the Upper Assembly
Line up the slide and barrel over the frame rails. If using a carbine or rifle-style kit, lock the upper using the rear hinge pin. This should feel smooth and snug.
Step 4: Insert Magazine + Test Fit
Once your internals and slide are in place, test the fit of your magazine. Don’t load any live rounds. Check slide movement, trigger pull, and reset.
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Step 5: Safety & Final Inspection
Make sure all pins are seated correctly, safeties function properly, and no parts are loose. Never test-fire inside your home. Only use legal, controlled environments.
Legal Warning for UK Buyers
In the UK, firearm possession is strictly regulated. You must not assemble or possess a functional firearm unless fully licensed. However, non-functional kits for education, training, and private ownership are legally sold and shipped.
That’s why all our kits at TopBoyGhostGuns.uk are shipped as non-functional or 80% kits, complying with UK privacy laws and guidelines.
Where to Buy Modular Firearm Kits in the UK
If you’re looking for trusted, UK-based sources of DIY firearm kits, choose TopBoyGhostGuns.uk — the leading provider of:
Every product comes with:
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✔️ Discreet UK shipping
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✔️ Educational usage statement
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✔️ Premium-grade parts with quality checks
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✔️ Assembly instructions or guide links
Final Assembly Tips
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Never over-tighten screws – use medium thread lock
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Clean all metal parts before first test fit
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Dry-fire test with dummy rounds (if legal in your area)
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Upgrade your frame with UK-compliant accessories from our shop
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Keep all builds strictly for private use
Ready to Start Building?
Building a modular firearm is a rewarding and educational process when done responsibly. For trusted parts, secure delivery, and full UK support, visit:
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Legal & Compliance Notice
This guide is for educational purposes only. TopBoy Ghost Guns does not endorse or sell completed firearms. All kits are sold under UK regulations for hobbyist, instructional, or non-functional use.
