Glock G37 Gen 3 45 GAP

The 45 GAP is a unique caliber that does exactly what it was designed to do. We like the G37, though we fear ammunition is a bit harder to obtain, and that’s reflected in the lower score.



$380 USED, $539 NEW

The new price is a recent cite from We’ve tested the G37 Gen 3 and gave it a Buy It rating in the past. Unfortunately, this go-round, the G37 received a slightly lower grade, but not due to the performance of the pistol. We still think this pistol performed well, but the issue is ammo availability. Not that the news of the 45 GAP’s demise is greatly exaggerated; 45 GAP is fairly easy to come by and as expensive as either 45 Auto or 10mm ammo. Federal and Remington have discontinued manufacture of the caliber, but Winchester, Sellier & Bellot, MagTech, Speer and Underwood websites all list the caliber. Finding this ammo in stock at a dealer is not likely, so we purchased our ammo online. Getting ammo for this pistol can be more difficult than the more-popular 45 ACP, and we have to ding it for that.

Action Locked breech, striker fire, semi-auto
Overall Length 8.03 in.
Overall Height 5.47 in.
Maximum Width 1.30 in.
Weight Unloaded28.75 oz.
Weight Loaded 35.27 oz.
Barrel 4.49 in.
Capacity 10+1 (double stack)
Slide Black, steel
Slide-Retraction Effort 13.0 lbs.
FrameBlack, polymer
Frame Front Strap Height 2.6 in.
Frame Back Strap Height3.4 in.
GripTextured polymer, finger grooves
Grip Thickness (max)1.3 in.
Grip Circumference (max) 5.7 in.
Sights Fixed; Trijicon 3-dot night sights
Trigger-Pull Weight 6.0 lbs.
Trigger Span 2.8 in.
Magazines 3; polymer
Manual Safety None
Warranty Limited One-Year
Made In Austria

The G37 uses the frame as a G17 (9mm), G22 (40 S&W), G31 (357 SIG), G34 (9mm) and G35 (40 S&W), but with a taller and wider slide to accommodate the 45-caliber cartridge. The slide of the G37 Gen 3 is 1.12 inches wide, and the width of a G17 Gen 3 slide is 1.0 inches, and you can see the difference in the G37 slide if you are accustomed to 9mm Glocks. The only difference between the G37 frame from the other guns was the ejector; it uses the same ejector as in the 45 Auto-chambered Glocks.

The Glock G37 sports Trijicon 3-dot tritium night sights, which offered a very good sight picture.

The idea behind the G37 was to fit 10 rounds of 45-caliber ammo in a 9mm-size pistol. As the story goes, Glock partnered with Speer to develop the 45 GAP (Glock Automatic Pistol). Most shooters consider the 45 GAP a shortened 45 Auto, and that is one way to describe the round, but the 45 GAP was really built from scratch to generate 45 Auto ballistics from a smaller case. It does not share the same case with 45 Auto, but is instead a rebated-rim round similar to the 40 S&W and 10mm.

Our sample was in excellent condition and came with three magazines and steel Trijicon Bright & Tough night sights with a three-dot white outline and green tritium inner dots. The tritium still glowed in this used pistol. We liked these sights because the front blade is wide, and there is plenty of space on both sides of the blade in the rear notch when aiming. We would have liked the front sight dot to be larger or maybe orange in color to help differentiate it from the two rear dots.

The G37 grip feels like a G17 grip because the grips are the same size.

Like all Glock Gen 3 pistols, there are finger grooves molded into the grip front strap and texture on the side panels and back strap. We think it is fair to say the grip looks dated compared to Glock’s Gen 4 and Gen 5 models, but there is a legion of Glock shooters who feel the Gen 3 guns are the best generation Glock has produced. We have also become accustomed to forward slide serrations, and we would have liked them on the G37 to more easily perform a press check.

The G37 employs the extended slide release used on G34s and G35s, and the magazine release is small compared to the ones on the LWD pistols and the S&W.

There is a bevel in the Glock G37’s magwell, and it allows the user to more easily and quickly insert a fresh magazine.

The magazines use a polymer body with witness holes in the back of the magazine. The follower and magazine body clearly state 45 GAP so the user won’t try to load 45 Auto, but we did anyway and found that 45 Auto ammo can be loaded in the 45 GAP magazines. Thankfully, the 45 Auto rounds will not chamber in the 45 GAP pistol. Still, be aware of the ammo you are using. The tenth round of GAP was difficult to load in the magazine. We used a Glock magazine loading tool from a G20 to top off the magazine to save wear and tear on our thumbs. We also found that it took a firm push to seat a fully loaded magazine into the pistol when the slide was forward. There is very little extra spring compression left in the magazine when fully loaded.

The trigger pull was typical Glock, with about 0.5 inch take-up and a 6-pound pull. There is a mushiness with Glock triggers followed by a consistent break. In our opinion, they are not a bullseye-style trigger by any means, but they are a very serviceable trigger.

On the Glock G37, the magazine release is small, but the slide release is oversized and extended similar to the slide stops used on the G34 and G35.

The G37 is a heavy pistol to tote, and we liked how the Bravo Concealment Kydex holster made carrying the pistol easy under a concealing garment.

The most accurate GAP load was the Speer Lawman 185-grain TMJ with a 1.6-inch five-shot group at 25 yards. The other loads were close on the Lawman’s heels. The Speer LE Gold Dot 200-grain GDHP load’s smallest group was 1.9 inches, and the Sellier & Bellot 230-grain FMJ was 2.1 inches. On average, however, all ammo shot 2-inch groups at 25 yards. We also found the Glock shot right on with no need to adjust the sights.

Going to the dynamic portion of the test, we found the 45 GAP could get away from you when firing the 10-yard stage requiring two quick body shots. The 45 GAP has a snap to it, though not as violent as the 10mm, but definitely more pronounced that the 45 Auto.

Our Team Said: The Glock worked flawlessly and had excellent accuracy. We think this pistol and this round has its purpose in self-defense situations. For those users wanting a pistol with a small-girth grip chambered in 45 caliber, this would be a good purchase. Because ammo is a bit more difficult to come by, we would buy ammo in bulk to ensure we have it on hand. A quality used G37 would be hard to beat if you’re willing to bet on ammo availability.

45 AUTO Range Data
Smith & Wesson M&P45 M2.0 CompactWinchester Train 230-gr. FMJFederal American Eagle 230-gr. FMJHPR 185-gr. JHP
Average Velocity 770 fps800 fps830 fps
Muzzle Energy303 ft.-lbs.327 ft.-lbs.283 ft.-lbs.
Smallest Group1.3 in.1.2 in.1.8 in.
Average Group1.4 in.1.6 in.2.2 in.
Lone Wolf Distributors TWL-LWinchester Train 230-gr. FMJFederal American Eagle 230-gr. FMJHPR 185-gr. JHP
Average Velocity797 fps809 fps963 fps
Muzzle Energy324 ft.-lbs.334 ft.-lbs.381 ft.-lbs.
Smallest Group1.7 in.1.0 in.0.7 in.
Average Group2.0 in.1.7 in.1.4 in.
10MM AUTO Range Data
Lone Wolf Distributors TWL-SBuffalo Bore 180-gr. JHPSIG Sauer V-Crown 180-gr. FMJHornady Critical 165-gr. FTX
Average Velocity 1317 fps1213 fps1222 fps
Muzzle Energy693 ft.-lbs. 588 ft.-lbs.547 ft.-lbs.
Smallest Group 0.8 in.1.6 in.2.0 in.
Average Group 1.3 in.1.9 in.2.2 in.
45 GAP Range Data
Glock G37 Gen 3Sellier & Bellot 230-gr. FMJSpeer Lawman 185-gr. TMJSpeer LE Gold Dot 200-gr. GDHP
Average Velocity 840 fps1027 fps943 fps
Muzzle Energy360 ft.-lbs. 433 ft.-lbs.395 ft.-lbs.
Smallest Group 2.1 in.1.6 in.1.9 in.
Average Group 2.3 in.2.1 in.2.0 in.


  1. a question for mr. sadowski if you please. i purchased a copy of the “book of glock” from gun tests some months ago. imagine my surprise when i found no mention of my made in austria model 21. do you know where can i find info on this model. thanks. i love the gun test magazines.

  2. The most accurate and easy to shoot Glock pistol that I have personally handled was my friend’s G37. I own a G26, 23 and 36 and his G37 outshot them all in my hand. He put his bet on 45 GAP by purchasing 2,000 rounds!!

  3. Why look for more trouble with getting ammo for a GAP when to the average target shooter, the ACP pistols are just as good without the aggravation of worrying about ammo. Your review was great, but so are the reviews on the ACP’s


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