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Fusion Firearms Glock +5 Magazine Extension Installation

Why install a mag extender?

Mag extenders give your Glock 17 magazines extra capacity and a bigger gripping surface for faster reloads and improved control. Our extenders come in five finishes — blue, red, gold, silver, and black — so you can match function with style.

Tools & parts you’ll need

  • Your unloaded Glock 17 magazine

  • New mag extender (we recommend Fusion mag extenders)

  • Replacement extended spring (included with the extender)

  • Small Phillips screwdriver (fits the base plate hole)

  • Small punch or thin flathead (optional)

  • Small hammer (optional, light taps only)

  • A paperclip or included tool (to retain guide/spring when reassembling)

Safety first — do this before you start

  1. Unload the magazine and verify there are no rounds in it.

  2. Make sure the firearm is unloaded and the slide is locked back before inserting or removing magazines.

  3. Work on the magazine away from live ammunition whenever possible.

  4. Follow all local laws regarding magazine capacity and accessories.

Step-by-step installation

  1. Remove the old base plate.
    Insert a Phillips screwdriver into the small hole in the magazine base plate. Apply upward pressure — the plate should pop off. Keep the original plate and the small keeper pieces in case you ever want to revert.

  2. Remove the spring & follower.
    Pull the spring and follower out carefully. Note how the spring sits in the follower so you can reassemble correctly.

  3. Swap in the extended spring.
    Place the new extended spring into the follower in the same orientation as the original. A small screwdriver can help seat it if needed.

  4. Prepare the extender halves.
    Identify the threaded half (this sits on top) and the non-threaded half (bottom). Slide the non-threaded portion onto the magazine body so it lines up with the keeper detent.

  5. Fit extender over the mag.
    Slide the threaded portion into the non-threaded bottom so the extender wraps around the mag. You’ll feel it hit the detent. If it’s tight, a few light taps with a hammer will help it seat — don’t hit hard.

  6. Install the lock screw.
    Insert the small lock screw through the hole and tighten with the small Phillips screwdriver. When installed properly, the screw head will sit on the outside of the magazine body (not inside). This screw keeps the extender locked in place.

  7. Reinstall spring & follower.
    Put the spring back in all the way down and reinstall the follower/keeper. Apply downward pressure as you slide the original base plate forward to lock everything in place. If it’s tight, tap the base plate forward until it seats.

  8. Check the detent.
    Use a small tool to press the mag detent lightly — the base plate should snap into place and stay secure.

  9. Load & function check.
    Load rounds (e.g., 17 + 5 with our extender), cycle the mag in your firearm, and perform a function check (again, ensure firearm is unloaded for safety checks except where you must test with dummy rounds or as per your safe range procedures).

Troubleshooting tips

  • Extender won’t slide on: make sure you’re aligning the threaded and non-threaded halves correctly. Light taps with a hammer often help seat it past the detent.

  • Screw ends up inside the mag: you’ve likely got the extender reversed — unscrew, flip the halves, and reinstall so the screw head is on the magazine outside.

  • Base plate won’t seat: check the follower orientation and ensure the spring is fully compressed while sliding the base plate forward. A light tap can help the plate pop into place.

Maintenance & care

  • Periodically check the lock screw for tightness. Use threadlocker if you plan heavy use, but only a removable (blue) variety so you can service the mag later.

  • Clean and lightly lubricate magazine components per Glock maintenance recommendations.

  • Inspect springs for wear; replace if they show deformation.

FAQ

Q: Will this work with Glock 17 OEM mags only?
A: The extender is designed for standard Glock 17-style magazines; results with aftermarket mags can vary.

Q: Is this legal everywhere?
A: Laws vary by state and country. Always check local magazine capacity restrictions before adding an extender.

Final notes

Installing a mag extender is a fast, mechanical mod that gives you extra capacity and a cleaner, more confident reload profile. Our Fusion mag extenders come in five finishes — blue, red, gold, silver, and black — so you can match your gear and stand out at the range.

Want one? Head to our product page to view colors and get installation videos and FAQs. If you run into any issues, drop us a note or bring your mag to the range and do a live function check with a qualified armorer.