How Does The G17 Gen4 Perform with Optics?

GLOCK G17 GEN4 MOS 9MM


The G17 Gen4 performed well with optics, and they were easy to install with plenty of adapter plates. We would have preferred taller sights. Compare a to a G17 Gen 3

g17 gen 4 mos

The Glock G17 Gen4 MOS (Modular Optic System) variant comes in a polymer carrying case with three magazines, four grip adapters — two with and two with out a beavertail — with a tool, and a mounting-plate kit consisting of four adapter plates, screws, wrench, and instructions. These adapter plates allow mounting of a reflex red-dot sight from Trijicon (RMR), Leupold (DeltaPoint), Meopta, C-More, Docter, EOTech, and Insight. We counted seven different sight options, which was more than the other pistols.

The G17 Gen4 MOS has a small cover plate just forward of the rear sight, which we removed. A razor was needed to initially separate the plate and the slide. We used the plate that corresponded to the Meopta and screwed that to the slide, then screwed the Meopta to the plate adapter. The standard sights did not co-witness with the optic. A set of tall aftermarket sights would cost an additional $110 to $150 from Glockstore.com, which would increase the total cost to $836-$876 and bring the money for the three pistols tested into the same range.

glock gen 4 grip inserts

The grip options included two with extended beavertails. The tool to remove the grip pin was included with the clip that held the extra backstraps.


The Gen4 series has a Rough Textured Frame (RTF) surface on the frame and the interchangeable back straps to enhance grip. We felt it did that without being too aggressive. Without a grip strap installed on the G17, the frame is a short-trigger-reach frame, or SF for “short frame.” Four additional backstraps were included, two with a beavertail and two without. The backstraps increased the trigger reach distance. We preferred to use the G17 sans backstraps. Also new in Gen4 pistols is a user-configurable ambidextrous magazine-release button. Gen3 magazines will work in Gen4 pistols if set up for a right-handed shooter, but will not work if the magazine release is set up for left-handed shooters.

glock gen 4 recoil spring

The Gen4 recoil spring assembly helped soften recoil.



Gen4 pistols also have an improved recoil-spring assembly with a dual recoil-spring setup designed to reduce felt recoil. We did notice that recoil was less with the Gen4 assembly. Another enhancement has been made to the trigger via a new disconnector. A pronounced dot or dimple is punched into the disconnector. We felt this new connector made the trigger break cleaner and much more predicable. The press still required 5.5 pounds, but we liked how this enhanced trigger broke.

At the range, we found we were more accurate and faster on target compared to iron sights using the Meopta. Accuracy was well under 2 inches at 25 yards using a rest. In fact, with the Winchester Train ammo firing a 147-grain FMJ, our smallest group was 0.8 inches, and, on average with this ammo, we were able to achieve 0.9-inch groups. This accuracy impressed us, and we feel the Gen4 trigger helped achieve that.

glock mos plate install

The adapter plate is first mounted to the slide, then the optic is mounted to the plate.



We did need ramp-up time to acquire the dot in the reflex sight for all pistols, since we are more familiar with iron sights, but once we were over that hump, we found that we could shoot faster and more accurately with a reflex sight than iron sights. The transition from iron sights to optic also requires the shooter to aim differently. Test members needed to lower the muzzle of the pistol slightly to acquire the red dot within the sight’s window. Within a few magazines, we were comfortable with the optic.

glock mos

The Glock’s iron sights were useless when the optic was mounted. Co-witnessing is better.

Our Team Said: The G17 Gen4 MOS performed well and gave users the most reflex sight options. It is a good choice for someone wanting a reflex sight on gun that could perform defense and competition duty, but we feel Glock should have added taller sights to co-witness with the optic.

test guns

Originally Published In July 2016.


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