G37 In .45 GAP


What the .45 ACP is to the 1911, the .45 GAP may become to the polymer pistol. There are plenty of satisfied customers out there with Glock 40s and 9mm pistols, but we think the G37 does the best job of managing recoil and blast while providing big-bullet stopping power.

glock 45 gap

From the outside there is little or nothing to distinguish the 37 from the well-known 17. Upgrades have mostly come in the form of refinements to the Glock’s ergonomics. The 37 features finger grooves, a palm swell, and mild but effective checkering molded into the polymer frame. Beneath the dust cover is an equipment rail with Picatinny fittings. The slide release has been reshaped from the original design to provide better access while remaining smooth and snag resistant. The top end features three-dot sights, rear-only slide serrations and an external extractor that protrudes noticeably when charged, providing an effective loaded-chamber indicator.

glock 45 gap

The Glock Model 37 is basically the same as the Model 17 chambered for .45 GAP. More polymer pistols chambered for Glock’s proprietary round may be in the offing, but for now the 37 is the only pistol chambered for the GAP. We used the 185-grain Speer Gold Dot Hollowpoints to print this group from 25 yards.


The Glock pistols break down to top end and receiver without having to remove a pin that could be easily lost. After dropping the magazine and clearing the chamber, the shooter presses the trigger to relieve the striker. Next, he retracts the slide about 0.25 inch or until the first slide serration is even with the rear of the frame. The best way to do this is to make a fist around the front of the pistol with the fingers over the top of the slide and the thumb below the dust cover against the outside of the trigger guard. With the slide retracted as above, use the thumb and index finger on your free hand to pull down on the slide-release levers located on each side of the frame directly above the trigger guard. The slide is then free to move forward and off the frame.

Inside was a linkless barrel with polygonal rifling and a guide rod assembly with a captured flat-wire spring. The primary contact points between slide and frame are two pairs of steel “skates” inlaid into the polymer rails fore and aft. Replacing the top end requires that you simply slide the top end back on to the frame. It will automatically latch once the slide is pushed all the way to the rear.

g37 slide assembly

The Glock top end breaks down to a slide with striker assembly, externally mounted extractor, that acts as a chamber-loaded indicator, a 4.5-inch barrel and a flat recoil spring captured on the guide rod.

Of our seven choices of .45 GAP ammunition available at retail, two featured 185-grain JHP bullets and one was topped with a 200-grain TMJ bullet, (totally jacketed, i.e. no exposed lead). The four remaining rounds weighed in with 230-grain bullets. Keeping in mind that 230-grain bullets are commonplace in .45 ACP loads, we found this wasn’t necessarily the ideal choice for .45 GAP. As explained in our evaluation of .45 GAP ammunition, lighter bullets contributed greatly to accurate repeat fire by helping keep the gun level. This shouldn’t come as a surprise because 230-grain .45 ACPs are renowned for muzzle flip and torque applied to the shooter as well as for their great stopping power.

Our best groups and most consistent rapid-fire session came when we loaded the 37 with 185-grain loads that would likely produce high-energy stopping power. The 230-grain JHP Winchester Ranger “T” law-enforcement round recoiled the most, and we felt that it was the extra control required that limited accuracy. The other two Winchester 230-grain rounds, a classic roundnosed FMJ slug and the WinClean truncated cone bullets, were more accurate but would still not be our first choices. We liked the accuracy and shorter shot-to-shot times we produced firing the Winchester STHP silver-tip hollowpoints the best. The most power and accuracy we were able to generate from the Glock 37 was with the Speer Gold Dot GDHP ammunition loaded with bullets weighing 185 and 200 grains respectively.


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Originally Published In June 2004.

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