FNS 40 Review: A Guide for New Gun Owners

The FN FNS-40 is a full-size, striker-fired, semi-automatic pistol chambered in .40 S&W. Built on a polymer frame with a stainless-steel slide and a hammer-forged barrel, it combines durability and precision.

With ambidextrous controls, interchangeable backstraps, and a standard 14+1 capacity, the FNS-40 delivers professional-grade performance suitable for duty, defense, and range use. Its crisp trigger, short reset, and solid construction make it a serious contender in the .40-caliber striker-fired market.

Credits

The FNS-40 represents FN America’s modern interpretation of a duty-grade striker-fired pistol chambered in .40 S&W — a cartridge once dominant among law enforcement agencies across the U.S. Designed and built at FN’s Fredericksburg, Virginia facility, this pistol was developed to meet agency-level durability requirements while maintaining comfort and control for civilian shooters.

FN Herstal’s legacy includes iconic military and police firearms such as the FN FAL, M249 SAW, and Five-seveN. The FNS series extended that lineage into striker-fired handguns, combining Belgian engineering with American production standards.

Intended primarily for duty and home-defense applications, the FNS-40 balances high capacity, crisp trigger feel, and ambidextrous operation — appealing to left- and right-handed shooters alike.

Its blend of reliability, build quality, and recoil management makes it equally suited for security professionals and serious range shooters looking for a robust .40 S&W option.

FNS 40 Specifications

Feature	Details
Type	Full-size semi-automatic pistol
Caliber	.40 S&W
Action	Striker-fired, double-action
Barrel Length	4.0 inches (cold hammer-forged stainless steel)
Overall Length	~7.25 inches
Height	~5.5 inches
Width	~1.35 inches
Weight (unloaded)	~27.5 oz
Frame Material	Polymer
Slide Material	Stainless steel
Magazine Capacity	14+1 (standard), 10-rounds optional
Sights	Fixed 3-dot (night sight upgrades available)
Rail	Integrated Picatinny accessory rail
Grip Customization	Interchangeable backstraps
Manufacturer	FN America
Release Year	~2011

FNS 40 Design & Build Quality

Materials & Construction

FN engineered the FNS-40 with a stainless-steel slide and cold hammer-forged barrel, both known for high corrosion resistance and mechanical longevity.

The polymer frame reduces overall weight while absorbing some recoil impulse from the snappier .40 S&W cartridge. FN’s finishing work — particularly on the slide and barrel — meets the same quality seen in their military-grade weapons.

Ergonomics & Grip

The pistol offers two interchangeable backstraps, enabling shooters to tailor grip size and angle. The grip texture is moderately aggressive, ensuring control during rapid fire without feeling overly abrasive.

Shooters with smaller hands note that the grip geometry feels blocky compared to a Glock 23, but others find the contouring and palm swell well-balanced for full-size handling.

Controls & Safety

The FNS-40 is fully ambidextrous, with slide stop levers on both sides and a reversible magazine release.

A trigger safety and internal striker block provide passive protection. Some models include an optional manual thumb safety. The decently weighted trigger features a short, tactile reset that experienced shooters appreciate for controlled follow-up shots.

Accessory Compatibility

A full-length MIL-STD-1913 rail allows the mounting of weapon lights and lasers — a must for home defense or duty carry. The FNS-40’s slide is not factory optics-ready, but aftermarket solutions exist for users interested in reflex sight capability.

FNS 40 Variants & Model Differences

• FNS-40 Standard: 4.0" barrel, 14-round capacity — standard duty configuration.

• FNS-40 Longslide: 5.0" barrel with extended sight radius, designed for enhanced accuracy and recoil control.

• Color and limited editions: Variants appeared in black, FDE, and two-tone stainless finishes.

Comparative models:

The FNS-40 frequently draws comparisons to the Glock 22, Sig Sauer P229, and Smith & Wesson M&P40. It offers similar reliability and build quality to those pistols, with the advantage of ambidextrous controls and a crisper trigger than many striker-fired .40s.

However, the slightly heavier frame and reduced aftermarket ecosystem keep it somewhat niche among casual owners.

Performance

Accuracy

At 15 to 25 yards, most shooters report 2.5" to 3" groups — excellent for a defensive .40-caliber handgun.

The cold hammer-forged barrel provides consistent lockup and accuracy over extended use. The longslide variant extends the sight radius, reducing shooter error and tightening groups even further.

Recoil & Control

.40 S&W has a sharper impulse than 9mm, but the FNS-40’s mass and grip geometry help manage muzzle flip effectively.

The recoil cycle is quick, and experienced shooters report easy reacquisition of sights for follow-up shots. Some users describe the recoil as “snappy but straight back,” without excessive muzzle rise.

Reliability

Reliability is where FN pistols shine. Across thousands of user reports, the FNS-40 exhibits near-flawless cycling with both FMJ and hollow-point ammunition.

Even under adverse conditions — rain, dust, or suppressed shooting in the Longslide variant — the pistol remains consistent. A small number of early recall issues were corrected, with post-recall models performing flawlessly.

Trigger

The FNS-40’s trigger is one of its standout features. It breaks cleanly around 5.5–6 lbs, with minimal creep and a short, tactile reset. Compared to Glock or M&P triggers, many shooters find the FNS-40’s to be slightly crisper, providing better shot predictability.

Ammunition Compatibility

• Ideal grain weights: 165–180 grain .40 S&W loads balance accuracy and recoil.

• Recommended defensive ammo: Speer Gold Dot 180 gr, Federal HST 180 gr, Hornady Critical Duty 175 gr — all proven performers.

• Target loads: 165-grain FMJ or 180-grain practice rounds from Federal, Winchester, or Blazer Brass.

• +P performance: While capable of handling +P ammunition, most shooters prefer standard-pressure loads for longevity and smoother recoil impulse.

• Feeding issues: Virtually none reported — the feed ramp design supports wide hollow point profiles.

FNS 40 Use Case Suitability

Concealed / Self-Defense

The FNS-40’s size and weight push it out of the subcompact carry category. However, its reliability and controllability make it a strong choice for open carry or winter concealed carry when layered clothing aids concealment.

Home Defense

Outstanding. The pistol’s high capacity, accessory rail, and crisp trigger make it a practical bedside companion. Add a weapon-mounted light and a 14-round magazine of premium defensive loads, and it’s a complete defensive setup.

Competition

The Longslide model finds favor with IDPA and USPSA shooters thanks to its extended sight radius and faster follow-up capability. While not purpose-built for competition, its clean break and predictable recoil make it competitive against other striker-fired .40s.

Outdoor / Field Use

.40 S&W isn’t a typical woods cartridge, but for those who want a reliable sidearm for hiking or vehicle carry, the FNS-40 provides durability and easy maintenance.

Range / Training

The crisp trigger and strong ergonomics make the FNS-40 enjoyable for extended range sessions. It’s an excellent pistol for shooters transitioning from DA/SA to striker-fired systems due to its intuitive trigger and reset feel.

Best Holsters for FNS 40 Firearms

Choosing the right FNS 40 holster depends on whether you prioritize concealment, comfort, or accessibility. The full-size frame requires a holster that offers firm retention and consistent draw alignment, especially when carrying on duty or in vehicles.

Cloak Tuck 3.5 IWB Holster

The Cloak Tuck 3.5 IWB holster for the FNS 40 holster allows discreet carry beneath clothing while maintaining full trigger guard coverage. Its flexible base and adjustable retention make it suitable for all-day comfort even with a full-size pistol.

Belt Holster

A belt holster for the FNS 40 holster provides firm retention and a balanced draw angle. It’s a favorite among law enforcement and security professionals who need stability and quick access without sacrificing comfort.

OWB Paddle Holster

The OWB paddle holster for the FNS 40 holster attaches securely yet removes easily, making it ideal for range use or off-duty carry. It allows rapid reholstering and consistent indexing during repetitive drills.

Swivel Drop Leg Holster

A swivel drop leg holster positions the FNS 40 holster low on the thigh for easy access when seated or wearing body armor. It’s ideal for tactical operations or training environments that demand unrestricted movement.

Chest Holster

Chest holsters are great for the FNS 40 holster when driving or wearing layered clothing. They keep the firearm centered and accessible while freeing the waist area for other gear.

Hook & Loop Holster

Hook & loop holsters offer flexible mounting options for the FNS 40 holster, ideal for packs or inside vehicle setups. They’re lightweight and adaptable, but should only be used where secure retention is ensured.

FNS 40 Pros & Cons

Pros:

• Excellent reliability across thousands of rounds

• Crisp striker-fired trigger with short, positive reset

• Durable stainless steel slide and hammer-forged barrel

• Ambidextrous controls for universal use

• Comfortable, customizable grip via backstraps

• Solid accuracy and predictable recoil impulse

• Full accessory rail for lights and lasers

Cons:

• Slightly heavier than comparable striker-fired .40s

• Magazine release can feel soft or indistinct

• Grip texture may be too aggressive for some users

• Limited aftermarket parts relative to Glock or M&P

• Not ideal for deep concealment due to full-size frame

Final Verdict

The FNS-40 stands as one of the most underrated pistols in the striker-fired .40 S&W class. It delivers superb reliability, solid accuracy, and a crisp trigger — all within a well-engineered frame built to FN’s exacting standards.

For law enforcement officers, home defenders, and shooters who still prefer the authoritative .40 S&W cartridge, it’s a serious contender.

Value for money: Despite limited aftermarket support, the FNS-40 often sells for less than equivalent duty-grade pistols while offering the same — or better — mechanical reliability.

Long-term ownership: FN’s customer service and build quality ensure longevity. Properly maintained, this pistol will easily outlast many polymer competitors.

Who should buy it: Choose the FNS-40 if you want a rugged, accurate, and proven .40-caliber handgun with professional ergonomics and minimal maintenance needs. Skip it only if you prioritize ultra-lightweight concealment or heavy aftermarket customization.