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Glock turns heads with MOS Configuration for Gen4 pistols

These new pistols, on display at SHOT Show 2015, will retain their surface hardness and factory warranty, and will be readily adaptable to new sight designs


Pictured is a .40 caliber Glock 35 Gen4 pistol with MOS Configuration.

PoliceOne Photo

With an estimated 65-plus percent share of the U.S. Law enforcement pistol market, Glock is a big fish in the pond, and when they move, they make waves. Thus, it’s interesting that the 2015 new product lineup from Glock is just as remarkable for what isn’t there, as it is for what is there.

What’s missing?

It’s no secret that a single-stack, 9mm pistol has been one of the most highly demanded models from Glock for a long, long time. When Glock surprised everybody with the .380ACP Model 42 last year, there was a collective gasp because it was not the 9mm everybody expected. It turns out that the 42 in the kurz is an excellent pistol in its own right, but for many, it merely whet the appetite for a big brother in the parabellum. Unfortunately, we’ll have to wait for that one, as it was absent again this year.

There was a full lineup of new Gen4 pistols to ease the disappointment, however. The “Modular Optic System” (MOS) Configuration was introduced on three favorites and one new design, and it turned lots of heads at SHOT Show. The MOS Configuration allows easy mounting of a reflex (“red dot”) sight on the rear of the slide, in a specially-relieved area just forward of the rear sight.

This relief cut accepts one of four mounting plates (included with each pistol) that are tailored to fit the most popular reflex sights on the market, including Trijicon, Leupold and C-More, among others. The mounts are securely attached via Torx screws.

There have been individuals modifying their older Glocks in a similar manner for years, but the milling of the slide left raw steel exposed (as opposed to the hardened, Tenifer surface from the factory) and the slide cuts were typically sight-specific in their dimensions.

These new pistols will retain their surface hardness and factory warranty, and will be readily adaptable to new sight designs (and dimensional changes) as they develop.

The MOS versions of the popular “Practical/Tactical” Models 34, 35 and 41 will doubtlessly appeal to competitors, and the new MOS configured Glock 40 (a brand new, long slide, 10mm pistol with 6.02 inch barrel) will probably become an instant classic with hog hunters.

Unfortunately, if any of these folks want to be able to use their traditional sights as a backup to the reflex sight, they will need to invest in a new pair of taller (i.e., “suppressor-ready”) front and rear sights, as the factory parts are too short to see through the lens of the mounted optic.

It’s important to note that while these 5.3 -6.2 inch, reflex sight-capable pistols might appeal to some LE users, they are not intended for duty roles. These pistols are sold with the competition-only, reduced weight connector which drops trigger pull weight to a nominal 4.5 pounds, which is short of the manufacturer recommended 5.5 pounds for all duty gun triggers.

Additionally, although great strides have been made in recent years with respect to reflex sight durability and battery life, there are still potential hurdles with water, blood or rain obscuring the view through the lens, fogging, holster incompatibility, and training issues which must be addressed before reflex sights are widely adopted for LE use.

Still, these pistols will add exciting capabilities in the sporting arena, and will encourage the training and development that will usher reflex-equipped guns into LE holsters. It’s going to be exciting to watch the MOS Configuration mature and expand to other models in the line, to include duty pistols sometime in the future.

Now if we could just get that elusive, single-stack, 9mm . . .

Mike Wood is the son of a 30-year California Highway Patrolman and the author of “Newhall Shooting: A Tactical Analysis,” the highly-acclaimed study of the 1970 California Highway Patrol gunfight in Newhall, California. Mike is an Honor Graduate of the United States Air Force Academy, a graduate of the US Army Airborne School, and a retired US Air Force Lieutenant Colonel with over 26 years of service. He’s a National Rifle Association (NRA) Law Enforcement Division-certified firearms instructor, senior editor at, and has been a featured guest on the Excellence In Training Academy and American Warrior Society podcasts, as well as several radio and television programs. He’s grateful for the opportunity to serve and learn from the men and women of law enforcement.