The Glock 40 Gen4 MOS (10mm) is engineered to deliver enhanced performance through extended barrel length and modular optic compatibility, setting it apart from other Glock 10mm platforms. While models like the Glock 20 and Glock 29 serve in duty or concealed roles, the Glock 40 Gen4 MOS is purpose-built for hunting, long-range accuracy, and red-dot integration right out of the box.

• Factory Modular Optic System (MOS): The slide comes pre-cut for optic mounting and includes adapter plates, allowing direct installation of popular red-dot optics without custom gunsmithing.

• Extended 6.02″ barrel: Offers increased muzzle velocity and energy, which enhances terminal ballistics, reduces bullet drop, and tightens groupings at longer distances—ideal for hunting and precision shooting.

• Long slide design: The added slide length not only increases sight radius for better iron sight alignment but also improves recoil control, aiding faster follow-up shots.

• Gen4 frame with backstraps: Customizable grip fit through interchangeable backstraps ensures better ergonomics across various hand sizes, improving control and comfort.

• Heavier and more balanced platform: The extra weight of the long slide and barrel balances recoil energy from powerful 10mm loads, offering a steadier shooting experience compared to shorter Glock models.

• Hunting and range-oriented: Its size and features make it better suited for open carry during hunts or competitive use, rather than everyday concealed carry.

• Superior optic co-witness options: With suppressor-height sights or proper optics, shooters can co-witness effectively, something not available on standard Glocks without aftermarket modifications.

Purchasing and owning the Glock 40 Gen4 MOS (10mm) depends entirely on the laws and regulations of your specific jurisdiction. At Brownell Glock, we ensure all transactions are compliant by verifying licensing and shipment restrictions before proceeding with any order.

• Permit and licensing requirements: Most regions require either a general firearms license, a specific handgun permit, or purchase authorization; we guide customers through submitting these legally required documents.

• FFL transfer mandates: In the United States, federal law often requires transfers to occur through a Federal Firearms License (FFL) dealer. We ship directly to your designated FFL when applicable.

• State and country restrictions: Certain states or countries ban or limit ownership of handguns with specific features (e.g., magazine capacity, optics cuts). We maintain a restriction list and will not ship to prohibited areas.

• Age and background eligibility: Buyers must typically be over 21 years of age and pass a background check or authorization process as per local laws. We help ensure your documentation supports eligibility.

• Export laws for international buyers: If you’re ordering from outside the U.S., we evaluate your country’s import and firearms laws. Some countries outright ban civilian handgun imports, while others require additional permits.

• Shipping limitations: Even where legal, we may not ship to regions with restrictive shipping carriers, political restrictions, or customs prohibitions related to firearms.

• Responsibility on the buyer: While we assist with documentation and verification, it’s ultimately your responsibility to understand the laws in your jurisdiction. We encourage consulting legal counsel if unsure.

The Glock 40 Gen4 MOS is designed with versatility in mind. Its Modular Optic System (MOS) slide accommodates a wide range of red-dot optics through the use of factory-supplied adapter plates, giving shooters access to various sighting solutions based on their preference or mission profile.

• MOS adapter plates: The pistol includes several interchangeable mounting plates that support the most common optic footprints such as Trijicon RMR, Leupold DeltaPoint, Docter/Noblex, and more.

• Micro red dot sights (MRDS): Compact sights like the Trijicon RMR Type 2, Holosun 507C, and Leupold DPP are ideal for handgun mounting and balance well with the long slide design.

• Co-witnessing with iron sights: Suppressor-height sights may be added to allow lower-third co-witness with red dots, ensuring redundancy in the event of optic failure.

• Battery and brightness access: Choose optics that offer top-loading battery compartments and tactile brightness settings for easier adjustments without removing the sight.

• Durability and recoil resistance: The 10mm round generates more recoil than 9mm or .40 S&W. Select optics specifically tested for high-recoil calibers to maintain zero and structural integrity.

• Torque specification adherence: When installing optics, always follow manufacturer torque guidelines. Over-tightening can crack mounting plates; under-tightening may cause optic shift.

• Backup options: In case you choose not to use an optic, the MOS slide includes a blanking plate to cover the mounting area and preserve the slide’s aesthetics and function.

The 10mm Auto is a potent cartridge, and the Glock 40 Gen4 MOS fully harnesses its ballistic potential with a long 6.02-inch barrel. This extended barrel length significantly improves velocity and terminal performance compared to compact or standard-length 10mm pistols.

• Higher muzzle velocity: A longer barrel increases dwell time and pressure buildup behind the bullet, resulting in higher speeds. This means better energy transfer and more reliable expansion with defensive or hunting loads.

• Improved accuracy: The increased sight radius (distance between front and rear sights) and enhanced bullet stability lead to better groupings at longer ranges.

• Greater effective range: Compared to shorter 10mm barrels, the Glock 40’s setup allows accurate shooting well beyond 50 yards, making it suitable for handgun hunting of medium-sized game.

• Reduced muzzle flip: The longer slide adds forward weight, mitigating muzzle rise and helping the shooter stay on target during rapid or follow-up shots.

• Enhanced bullet performance: Full-power 10mm loads, such as 180gr or 200gr hardcast bullets, benefit from added barrel length—achieving full powder burn and optimal trajectory for deep penetration.

• Energy delivery: The 10mm outperforms .45 ACP and .40 S&W in foot-pounds of energy when fired from a long barrel, making it one of the top choices for defensive backcountry use.

• Hunting legalities: In many states, a 10mm handgun with a 6-inch barrel meets legal minimums for hunting deer and other medium game, adding to its field versatility.

The Glock 40 Gen4 MOS uses Glock factory magazines designed for the 10mm Auto cartridge. It offers reliable feeding with standard capacity mags and supports aftermarket or extended options as well. Understanding magazine compatibility is crucial for optimal function.

• Factory 15-round magazines: These are the standard magazines supplied with the Glock 40 Gen4. They feature a durable polymer body with steel reinforcement and anti-tilt followers.

• Gen4 compatibility: Ensure your magazines are rated for Gen4 frames. While some Gen3 mags may fit, Gen4 designs account for reversible mag catch and improved fitment.

• Aftermarket extended baseplates: Brands like Taran Tactical and Arredondo offer extensions that can increase capacity by +2 to +5 rounds. These are ideal for range use or backcountry carry.

• Magazine maintenance: Clean magazines regularly to remove grit, carbon, or moisture. Replace springs and followers every few thousand rounds to avoid feeding issues.

• Interchangeability with Glock 20: The Glock 40 Gen4 shares magazine compatibility with the Glock 20. This allows for easier backup and spare mag procurement.

• Avoid counterfeit mags: Use only genuine Glock or high-quality aftermarket magazines. Poorly made replicas can cause feeding failures or damage your firearm.

• Carrying spares: Due to the power of the 10mm, it’s common to carry multiple magazines when hiking or hunting. Use mag carriers with retention systems for secure transport.

Routine maintenance is essential to keep your Glock 40 Gen4 MOS running flawlessly—especially when firing full-power 10mm loads, using mounted optics, or operating in outdoor environments. A consistent cleaning and inspection schedule not only preserves accuracy but also prevents premature wear or failure under stress.

• After each range session: Field-strip the pistol to clean carbon fouling from the slide, barrel, feed ramp, recoil assembly, and breech face. Use Glock-approved solvents and non-abrasive brushes.

• Every 300–500 rounds: Inspect key wear components such as the recoil spring assembly, slide rails, and extractor. Replace any parts showing signs of fatigue or damage.

• Optic system checks: Retorque the optic mounting screws after the first 50 rounds and then periodically. Ensure zero is maintained and no shift has occurred due to recoil.

• Quarterly deep clean: Disassemble internal components (trigger group, striker assembly, safety plunger) and clean out the striker channel, firing pin safety, and trigger mechanism with care.

• Annual inspection by a professional: Have a certified Glock armorer or licensed gunsmith conduct a full breakdown once a year, especially if the firearm is used for duty, defense, or hunting.

• Magazine maintenance: Remove dust, grit, and oil buildup from magazines every few months. Replace springs and followers when you notice weakened feeding tension.

• Recoil spring replacement: Glock recommends replacing the dual recoil spring assembly approximately every 3,000–5,000 rounds to maintain optimal cycling with the 10mm cartridge.

Yes, but modifications are required. The factory Glock 40 Gen4 MOS comes with a non-threaded barrel, so you’ll need an aftermarket threaded barrel to mount a suppressor or compensator. Once installed, proper fitment and legal compliance become essential for safety and function.

• Aftermarket threaded barrels: Choose a reputable 10mm threaded barrel designed specifically for the Glock 40 Gen4. Ensure thread pitch matches your chosen accessory (e.g., 9/16×24 for many 10mm barrels).

• Suppressor compatibility: You must ensure the suppressor is rated for 10mm pressure levels. Sub-par cans not designed for 10mm could fail catastrophically.

• Thread protector usage: If using a threaded barrel without an attachment, always install a thread protector to avoid thread damage during use or transport.

• Compensator benefits: A compensator can significantly reduce muzzle rise and felt recoil, especially helpful with full-power loads or in rapid-fire shooting. Installation must be secure to avoid loosening.

• Legal considerations: Suppressors are regulated under federal law and are illegal in some jurisdictions. A federal tax stamp and background check may be required to own one.

• Point of impact shift: Adding a suppressor or compensator can affect point of impact and cycling. Always test and re-zero your optics or sights after installation.

• Holster fitment: With attachments installed, standard holsters may no longer fit. Use a custom or open-ended holster designed to accommodate extended muzzle devices.

The Gen4 grip system is designed to improve ergonomics, recoil management, and shooter confidence across a wide range of hand sizes. By offering interchangeable backstraps and a textured surface, the Glock 40 Gen4 MOS enhances your ability to maintain a secure grip during powerful 10mm recoil cycles.

• Interchangeable backstraps: The pistol comes with multiple backstrap options (medium and large, with or without beavertail). These help adjust trigger reach and grip circumference for personalized comfort.

• Improved control under recoil: A tailored grip fit reduces slippage and improves the shooter’s ability to manage the 10mm’s recoil impulse—essential for accurate follow-up shots.

• Beavertail backstrap benefits: This option protects the shooter’s hand from slide bite and offers a more consistent high grip, which enhances leverage and control.

• Enhanced texture: The Gen4’s stippling increases friction against gloves or sweaty hands, minimizing the risk of slippage during defensive or high-stress shooting.

• Natural point-of-aim: A properly fitted backstrap helps align the bore axis naturally with your wrist and forearm, reducing muscle fatigue and improving accuracy.

• Gloved shooting compatibility: The Gen4 frame’s ergonomics and texture support secure handling even when wearing tactical gloves—important for hunting or outdoor defense.

• Modular fit across users: In shared or training environments, the Gen4 grip system allows easy reconfiguration between shooters of different hand sizes.

The Glock 40 Gen4 MOS incorporates Glock’s signature Safe Action® System—a set of three passive mechanical safeties that work independently and sequentially. These features are engineered to prevent accidental discharge while ensuring instant readiness when the shooter engages the trigger properly.

• Trigger safety: A spring-loaded tab in the center of the trigger prevents it from moving rearward unless the tab is deliberately pressed, ensuring the trigger isn’t activated by lateral pressure or snags.

• Firing pin safety: A solid steel plunger blocks the firing pin from moving forward unless the trigger is pulled fully to the rear. This prevents the striker from contacting the primer without intentional engagement.

• Drop safety: Internal components are designed so the trigger bar remains in a resting position that blocks the firing pin, even if the pistol is dropped or jarred violently.

• Passive system—no manual switch: The Glock design omits external safety levers, favoring a streamlined design that minimizes failure points and enables immediate deployment in high-stress environments.

• Internal safeties reset after each shot: All three safeties automatically reset as the slide cycles, ensuring the pistol is always protected unless the trigger is intentionally pressed.

• Loaded chamber indicator: The extractor protrudes slightly when a round is chambered, providing both visual and tactile confirmation of a loaded firearm.

• Reinforced holster safety: With no manual safety, proper holstering becomes even more critical. Use rigid, trigger-guard-covering holsters to prevent accidental trigger contact during carry or draw.

Storing your Glock 40 Gen4 MOS properly is vital for safety, legal compliance, and long-term firearm health. Due to its power and size, this model is typically not a daily concealed carry pistol, making secure storage even more important between uses.

• Locked firearm safes: Store the pistol in a certified gun safe that prevents unauthorized access. Choose models with biometric or combination locks for quick access during emergencies.

• Humidity control: Use dehumidifiers or silica gel packs inside your safe to prevent moisture buildup, which can cause corrosion on metal components and optic screws.

• Cable or trigger locks: For added safety—especially in homes with children—use a cable or trigger lock, even inside a safe, to create layered protection.

• Separate ammo storage: Store ammunition in a different locked compartment or container to reduce risk in case of unauthorized access and comply with regional regulations.

• Storage orientation: Store handguns in horizontal cradles or padded sleeves that prevent pressure on optics, sights, or threaded barrels.

• Routine checks: Periodically inspect the pistol for signs of moisture, rust, or degradation—especially if stored long-term. Rotate ammunition every 6–12 months if kept loaded.

• Legal compliance: Some states and countries have specific gun storage laws (e.g., mandatory locking containers or safes). We encourage you to verify and follow your local regulations.