Glock 40 Review (2026): The 6-Inch 10mm Glock, 800 Rounds Tested

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Table of Contents

Review: Glock 40 Gen4 MOS – The 10mm Glock That Went Back Behind the Counter

Our Rating: 8.1/10

• Street Price: $599.99 (Use our live pricing for the best up to date deal)
• Caliber: 10mm Auto
• Action: Striker fired, Glock Safe Action
• Barrel Length: 6.02 in.
• Overall Length: 9.49 in.
• Slide Length: 9.02 in.
• Height (with magazine): 5.47 in.
• Width: 1.34 in. overall, 1.12 in. at the slide
• Weight: 32.28 oz without magazine, 35.45 oz with an empty magazine, 44.62 oz loaded
• Capacity: 15+1
• Trigger Pull: 24 N per Glock, about 5.4 lb
• Optics: MOS cut slide with a cover plate
• Frame: Gen4 polymer with modular backstraps and a reversible magazine catch

Quick Take

The Glock 40 is a Glock 20 with a 6.02 inch barrel and a slide cut for a red dot. That’s the whole idea, and it’s a good one. The extra length buys velocity, the extra weight soaks up recoil, and the long sight radius makes it the easiest 10mm Glock to shoot well past 25 yards. It was built for handgun hunters and for people who want a 10mm that feels tame.

Here’s what most reviews miss. Glock’s own US website now files the G40 Gen4 MOS in its law enforcement catalog, with the product record flagged law enforcement only. The commercial catalog lists no G40 at all, and its only 10mm is the new G20 V MOS. When I checked prices on September 25, 2026, just three retailers we track had a new Glock 40, and none of them was one of the big five.

This Glock 40 review is built on 800 rounds over three range sessions, plus a chronograph day against a Glock 20. So is it still worth buying? Yes, if you want the most shootable 10mm Glock and you can find one near $600. It’s the pistol I’d take into the woods. Just don’t wait for a Gen5 or V version, because Glock’s catalog doesn’t show one.

Best For: Handgun hunters, backcountry carry in a chest rig, and anyone who wants a 10mm that shoots flat and soft. Not for concealed carry, and not for anyone who needs a gun they can walk into any store and buy.

Design Intent: Why Glock Built a Six-Inch 10mm

The 10mm has always been a cartridge that wants barrel. Give it more length and it keeps accelerating, which is exactly what you want for hunting and for stopping something large. The standard Glock 20 runs a 4.61 inch barrel. The G40 stretches that to 6.02 inches on the same big 10mm frame, then adds the MOS cut so you can bolt a red dot straight to the slide. Glock’s own description says it “combines a long slide and barrel for improved velocity with a high magazine capacity,” and that’s an honest summary.

It’s a Gen4 gun, so you get the Gen4 frame texture, the modular backstraps and the reversible magazine catch Glock lists on its own page. You don’t get the Gen5 frame, and you don’t get the newer V design either.

The listing change nobody mentions

I went through Glock’s US product catalog to confirm the specs, and the interesting part was the metadata. Every Gen4 and Gen5 pistol record on that page, from the G17 to the G41, is flagged law enforcement only, the G40 among them. The records without the flag are the V models, the three Gen6 pistols and the single-stack slimlines. For 10mm that means one pistol, the G20 V MOS. There is no G40 V and no long-slide 10mm in Glock’s commercial lineup.

I wouldn’t call the Glock 40 discontinued in so many words, and that doesn’t make it illegal to own or sell. It means what’s on dealer shelves now is the last of the stock, and it shows. Our catalog had only three new G40 listings, from $599.99 to $708.40, and the only one at a big trusted retailer was a Guns.com listing at $2,999.99 that I’d ignore. If you want one, buy it when you see it near $600.

Glock 10mm Variants: G40 vs G20 V vs G29

Glock 40 vs Glock 20 comes down to barrel. Glock lists the Glock 40 10mm at 6.02 inches, 9.49 inches overall and 32.28 oz without a magazine, against 4.61 inches, 8.07 inches and 25.22 oz for the G20 V MOS, and both hold 15 rounds. The G40 itself only comes one way: Gen4, MOS, 15 rounds. So the real variant question is which 10mm Glock you want. Glock’s own spec pages make the trade very clear.

Against the G20 V you’re paying 7.06 ounces and 1.42 inches of length for 1.41 inches of barrel. Capacity is the same 15 rounds, and the height is almost identical at 5.47 inches against 5.51. Glock even lists the G40 trigger lighter, 24 N against 26 N on the G20 V. The subcompact G29 goes the other way: a 3.78 inch barrel, 10 rounds and a 28 N trigger, and it’s also on the law enforcement list now.

Competitor Comparison

I compared the Glock 40 against four 10mm pistols priced on September 25, 2026: the Glock 20 V MOS at $620, the S&W Performance Center M&P 10mm at $649, the SIG P320 XTEN at $829.99 and the Springfield XD-M Elite at $589.99. The three new Glock 40 listings I found were $599.99 at Sportsmans Outdoor Superstore, $700 at Classic Firearms and $708.40 at Farnsworth Firearms.

Glock 20 V MOS (from $620)

This is what Glock sells civilians now, and for most people it’s the smarter buy. It’s lighter, it’s the 10mm Glock still on Glock’s commercial list, and Brownells had it in stock. Brownells had it at $620 on September 25. What you give up is the barrel. In my chronograph testing the G40 ran 53 to 61 fps faster with all three loads I shot through both guns, and the longer sight radius made the difference obvious at 50 yards. If you’re hunting, the G40 still wins. For carry in the woods, the G20 V is easier to live with. Our Glock 20 Gen 5 review covers the standard-length gun in detail.

Smith & Wesson Performance Center M&P 10mm M2.0 (from $649)

Smith & Wesson’s long slide is the G40’s closest rival: a 5.6 inch barrel and 15 rounds, from a maker that still sells it to everyone. I find the M&P grip easier to hold than the big Glock frame, and its trigger broke cleaner for me. Brownells had the 5.6 inch gun at $649 on September 25. If you can’t find a G40, this is where I’d go.

SIG Sauer P320 XTEN (from $829.99)

The XTEN runs a 5 inch barrel and 15 rounds with an optic cut, and it costs about $230 more than the G40’s card price. I like its trigger more than any Gen4 Glock’s. The G40 still carries a full inch more barrel, and for hunting that matters to me more.

Springfield XD-M Elite 10mm (from $589.99)

The cheapest gun here that holds more rounds, 16+1 from a 4.5 inch barrel. It’s a solid 10mm with an optic-ready slide, and its stock trigger felt better to me than any Gen4 Glock’s. It isn’t a long slide, though, so it competes more with the G20 than the G40. Brownells had it at $589.99.

Verdict: If you want the longest barrel and the softest shooting 10mm Glock, the G40 is still the one, while you can find it. If availability matters more than the last 60 fps, buy the G20 V or the Performance Center M&P.

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Testing Protocol

I fired 800 rounds of four 10mm loads through the Glock 40 over three range sessions, logged velocity on a chronograph and measured an average 5 lb 8 oz trigger pull.

Ammunition Log

• Federal American Eagle 180 gr FMJ: 400 rounds
• Hornady Custom 180 gr XTP: 150 rounds
• Sig Sauer Elite V-Crown 180 gr JHP: 150 rounds
• Underwood 200 gr Hard Cast Flat Nose: 100 rounds
• Total: 800 rounds over three range sessions

Phase 1: Break-In

The first 200 rounds were all American Eagle FMJ on a cool, dry September morning, about 55 degrees. I shot it straight out of the box after wiping off the factory oil and adding a drop on the slide rails. No stoppages. Brass landed in a tidy pile about six feet to the right, and the slide locked back on empty every time.

Phase 2: Reliability

Rounds 201 to 800 mixed the other three loads with the rest of the FMJ over two more sessions. The gun had one stoppage in total: a failure to feed at round 212, the twelfth Underwood hard cast round, where the wide flat nose stubbed on the feed ramp. A slap on the magazine and a rack cleared it, and the other 88 hard cast rounds fed fine. The XTP and V-Crown hollow points ran clean. I didn’t clean it until the end, and it never slowed down.

Phase 3: Accuracy and Velocity

I shot five-shot groups off a bag at 25 yards, first with the factory polymer sights and then with a red dot on the MOS plate. With irons my groups averaged 2.9 inches, best 2.1. With the dot they averaged 2.2 inches, and the best was 1.6 inches with Hornady’s 180 gr XTP. The trigger measured 5 lb 8 oz on average on my Lyman gauge, close to Glock’s 24 N figure.

I also ran three loads over a chronograph through the G40 and a Glock 20 on the same day. Ten-shot averages:

Load	Glock 40 (6.02 in.)	Glock 20 (4.61 in.)	Gain
Federal American Eagle 180 gr FMJ	1,088 fps	1,027 fps	+61 fps
Hornady Custom 180 gr XTP	1,252 fps	1,194 fps	+58 fps
Underwood 200 gr Hard Cast	1,268 fps	1,215 fps	+53 fps

Tracking & Observations

After 800 rounds the barrel hood and locking block showed the usual polished wear lines and nothing more. The recoil spring assembly was fine. The MOS cover plate screws stayed tight through the whole test, and so did the dot once I’d mounted it with thread locker.

What This Means for You

• Upgrade Impact: A red dot does more for this gun than any trigger swap.
• Reliability: Round nose and hollow points ran clean; test any hard cast load first.
• Ammo Preference: It liked the 180 gr XTP best.
• Maintenance: Standard Glock care; keep the MOS screws locked.
• Accuracy Expectation: About 2 inches at 25 yards with a dot and good ammo.

Performance Testing Results

The Glock 40 ran 800 rounds with a single stoppage, caused by a flat-nosed hard cast bullet, and earned 9/10 for both reliability and accuracy in my testing.

Reliability (9/10)

One stoppage in 800 rounds, and it came from a flat-nosed hard cast bullet that plenty of pistols dislike. With round nose FMJ and modern hollow points it simply ran. That’s what you buy a Glock for.

Accuracy (9/10)

The long sight radius is the difference you feel first. With irons it’s easier to hold a steady picture than on a G20, and with a dot the gun shot 2.2 inch averages at 25 yards. For deer-sized game at pistol distances that’s plenty.

Ergonomics & Recoil (7/10)

Recoil is the pleasant surprise. At about 44 ounces loaded, the G40 turns full power 10mm into a firm push rather than a snap, and the muzzle comes back down fast. The grip is the old problem. It’s the big 10mm frame, and even with the smallest backstrap a friend with smaller hands couldn’t reach the trigger comfortably. Try one before you buy if your hands are on the small side.

Fit, Finish, and Quality Control (8/10)

Nothing to complain about and nothing to brag about. The slide finish is even, the frame molding is clean and the markings are crisp. It is a Glock.

Technical Deep Dive

Slide, Barrel and Sight Radius

The slide is 9.02 inches long against 7.52 on the G20 V, and Glock lists the polymer sight line at 8.31 inches against 6.93. That extra 1.38 inches of sight radius is why the G40 is easier to shoot with irons. The barrel is 6.02 inches, the longest in Glock’s 10mm lineup.

MOS Optic Cut

MOS stands for Modular Optic System. The slide comes with a cover plate over the cut, and you swap it for the adapter plate that matches your dot. Glock says the system lets you mount a reflex sight “without the need for a new slide or separate mounting system.” On a long slide that’s the right call, since a dot is the best upgrade this gun can get.

Frame and Grip

It’s the Gen4 large frame with interchangeable backstraps and a magazine catch you can reverse for left-handed shooters. The trigger distance, the reach from backstrap to trigger face, is 2.85 inches on Glock’s sheet, the same as Glock lists for the G20 V MOS and G29.

Spec (Glock’s figures)	Glock 40 Gen4 MOS	Glock 20 V MOS	Glock 29 Gen4
Barrel	6.02 in.	4.61 in.	3.78 in.
Overall length	9.49 in.	8.07 in.	6.97 in.
Height with magazine	5.47 in.	5.51 in.	4.53 in.
Weight, no magazine	32.28 oz	25.22 oz	24.34 oz
Weight, loaded	44.62 oz	37.21 oz	32.63 oz
Capacity	15	15	10
Trigger pull	24 N	26 N	28 N
Glock listing	Law enforcement	Commercial	Law enforcement

Parts, Accessories and Upgrades

The Glock 40 ships with an MOS cut and a cover plate, so the first upgrade is a full-size pistol dot on the matching adapter plate, then a holster made for the 9.02 inch slide. Our Glock 20 parts and accessories guide covers frame-side upgrades for the same large 10mm frame.

Upgrade Category	Recommended Component	Why It Matters	Cost Estimate
Red dot	A full-size pistol dot on the matching MOS plate	The single biggest accuracy gain on this gun	$250 – $500
Holster	A chest rig or long-slide OWB holster	Most G20 holsters are too short	$60 – $150
Ammo	180 gr JHP for defense, hard cast for large animals	Match the bullet to the job	$1 – $2 per round
Spare magazines	Factory Glock 15-round 10mm	One per session is never enough	$30 – $40

For loads, our best 10mm ammo guide breaks down defense, hunting and range choices, and 10mm for bear defense covers what to carry in the backcountry.

Common Problems & Solutions

• Finding one new: With the G40 off Glock’s commercial catalog, stock is thin. Set a price alert, and check the card above before paying over about $700.
• Holster fit: A G20 holster won’t cover the long slide and barrel. Buy one made for the G40 or a chest rig with an open bottom.
• Hard cast feeding: Wide flat nose bullets can stub on the ramp. Test your hunting load for at least 50 rounds before trusting it.
• Loose dot: Use the correct MOS plate and blue thread locker on the screws, and check the torque after the first 100 rounds.

Who Should NOT Buy This Gun

• Concealed carriers: at 9.49 inches long it doesn’t hide. Look at the Glock 29, if you can find one, or our best 10mm carry pistols instead.
• Buyers who want a gun they can find anywhere: the Glock 20 V MOS is on Glock’s commercial list and uses the same caliber.
• Shooters with small hands: the S&W Performance Center M&P 10mm was easier for smaller hands to hold in my testing, and it has a similar long barrel.
• Anyone who wants the cheapest 10mm: the Springfield XD-M Elite 10mm costs less and holds a round more.

Final Verdict

The Glock 40 is still the best 10mm Glock for hunting and for anyone who wants the cartridge without the snap. In my opinion it’s the 10mm Glock to pick for hogs, and for a woods gun where bear are a concern. The long barrel added about 60 fps on every load I tested, the extra weight tames recoil, and the MOS slide makes a dot easy. After 800 rounds it had one hard cast hiccup and nothing else.

The catch is availability. Glock’s US site now lists the G40 only in its law enforcement catalog, and the three new listings we could find ran $599.99 to $708.40. If you see one in that range, buy it. If not, the G20 V MOS or the Performance Center M&P 10mm will serve you well. Compare them in our best 10mm pistols roundup, and if you’re choosing between cartridges, read 9mm vs 10mm first.

Final Score: 8.1/10 – The softest shooting, flattest shooting 10mm Glock, and it’s getting hard to find.

Specs in this review come from Glock’s own product pages for the G40 Gen4 MOS and the G20 V MOS. Prices are what readers saw on our live price cards on September 25, 2026.

FAQ: Glock 40