Barrel — G39 | OEM-Style Replacement for Glock® 39 (.45 GAP) | Part 4002

Restore Factory Accuracy & Reliability to Your Glock 39

Bring your subcompact back to peak performance with the Barrel — G39 (Part 4002), a .45 GAP factory-spec replacement engineered for the Glock® 39 platform. Built to Glock-style tolerances and featuring polygonal-style rifling with a durable, wear-resistant finish, this drop-in barrel helps deliver the tight lockup, consistent velocities, and repeatable point of impact you expect from a carry pistol.

Model Compatibility: Glock G39 (subcompact, .45 GAP)
Caliber: .45 GAP • Length: ~3.43" (87 mm), factory subcompact length
Rifling: Polygonal-style • Muzzle: Standard (non-threaded)
Part Number: 4002

Why Choose the G39 Barrel (4002)?

Factory-Spec Dimensions for True Drop-In Fit

Machined to OEM-style dimensions, the 4002 locks up cleanly with your G39 slide and factory recoil system for reliable cycling and consistent ejection.

Polygonal-Style Rifling for Performance

The smooth, polygonal-style bore profile supports excellent gas seal, helping maintain velocity and delivering easy-to-clean performance compared to traditional land-and-groove rifling.

Durable, Corrosion-Resistant Finish

The hard, wear-resistant surface treatment resists holster rub, humidity, and routine cleaning chemicals—ideal for daily concealed carry and high-round-count practice.

Optimized for Defensive & Training Loads

Chambered in .45 GAP, this barrel is tuned for common bullet weights used in both practice FMJ and quality JHP loads (always test your specific ammunition for function).

Key Features at a Glance

• Direct replacement barrel for Glock 39 (.45 GAP)

• Standard subcompact length (~3.43") for factory balance and reliability

• Polygonal-style rifling for accuracy and ease of maintenance

• Non-threaded muzzle for duty/carry compliance

• Wear- and corrosion-resistant finish for long service life

• Part #: 4002

Fitment Note: Designed for the G39 subcompact in .45 GAP. Not compatible with other Glock models or calibers. Always verify your slide and frame markings before purchase.

What You’ll Notice on the Range

• Repeatable POI & tight groups from solid barrel-to-slide lockup

• Smooth recoil impulse with consistent ejection patterns

• Fast cleanup thanks to the slick, polygonal-style bore surface

Ideal Use Cases

• Carry Pistol Refresh: Replace a high-mileage tube to restore accuracy

• Training Workhorse: Maintain reliability for classes and quals

• Armorer Stock: Keep spares on hand for agency or range fleets

Installation & Use (High-Level)

1. Unload & Clear the firearm; remove the magazine and inspect the chamber.

2. Field Strip the pistol, remove the old barrel and drop in the G39 4002.

3. Reassemble & Function Check for proper lockup and slide travel.

4. Range-Verify with your intended carry and practice ammunition.

For best results, follow Glock-safe cleaning practices and avoid the use of unjacketed lead bullets in polygonal-style bores.

FAQs

Q: Will this barrel fit other .45 GAP Glocks like G37 or G38?
A: No. This is model-specific for the G39 subcompact. The G37/G38 use different barrel lengths and profiles.

Q: Is this threaded?
A: No. It’s a standard, non-threaded subcompact barrel suitable for duty/carry policies that prohibit threads.

Q: Do I need a gunsmith?
A: Most users can drop-in install during a standard field strip. If you encounter fit questions, consult a certified armorer.

Q: What ammo should I test?
A: Run your intended carry load and a reliable training FMJ. Confirm point of impact and cycling before carry.

SEO-Rich Highlights & Buyer Keywords

• Glock 39 barrel replacement .45 GAP — Part 4002

• OEM-style G39 barrel with polygonal rifling, non-threaded

• Restore factory accuracy and reliability for concealed carry

• Subcompact 3.43" barrel for Glock 39, durable finish

• Drop-in fit .45 GAP G39 barrel, armorer-grade spare

Meta Title (SEO)

Barrel — Glock 39 (.45 GAP) OEM-Style Replacement | Part 4002 | Subcompact 3.43"

Meta Description (SEO)

Replace your worn tube with the G39 Barrel (Part 4002)—OEM-style, .45 GAP, ~3.43" subcompact length, polygonal-style rifling, and durable finish. Drop-in fit for Glock 39 to restore accuracy and reliability.

Structured Data (Product Schema JSON-LD)

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  "category": "Sporting Goods > Outdoor Recreation > Shooting > Gun Parts",
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Responsible Use Reminder

Always ensure the firearm is unloaded before maintenance. After installing any new barrel, function-test with your intended ammunition, verify point of impact, and follow all local, state, and federal laws. Practice safe storage and handling at all times.

The End