CMMG MkG 9mm GUARD/Vortex Razor® AMG™ UH-1™ Holographic Sight

The UH-1’s housing “disappears” when focusing on the holographic projected reticle.

Innovations in AR Platform and Optics Make a Perfect Team

The urge to take advantage of AR modularity, ergonomics, optics mounting and accuracy with cartridges other than 5.56mm cartridge has constantly appealed to the shooting community. CMMG has experience with this in the form of their highly successful Mk47 Mutant 7.62×39 and MkW ANVIL .458 SOCOM rifles. CMMG has taken this a step further with their new MkG GUARD platform.

The CMMG MkG GUARD is not merely another 9mm blowback AR-pattern weapon. CMMG has designed a patent pending Radial Delayed Blowback (RDB) operating system. The advantages are numerous for both manufacturer and, more importantly, the user. CMMG is able to reduce manufacturing cost by using similar tooling, methods, parts and techniques familiar to the AR-15 versus the hunk of metal typical of the bolt group from previous blowback AR SMG models. The user is rewarded with a 9mm AR rifle that is not only lighter overall but also offers lighter recoil during use. This is because a heavy bolt mass is no longer needed to control pressures as in a strictly blowback operating method.

The CMMG RDB rotates and unlocks (a la AR-15) before cycling to the rear versus just moving rearward upon a round being fired and thus slows the bolt carrier group enough to allow pressure to drop, allowing for safe functioning. The CMMG MkG GUARD’s bolt carrier is much lighter than a 9mm AR using standard blowback method. This translates into less recoil and a more controllable rifle in rapid fire since the pound or more metal mass is no longer recoiling rearward then slamming forward again.

CMMG MkG 9mm GUARD AR pistol with a Vortex Razor AMG UH-1 optic mounted combine for a near perfect tandem.

A trend that can be no longer ignored or dismissed as a passing fad is the number of pistol models stemming from what was typically associated with rifle pattern weapons via removing the buttstock. AR-type pistols are dominating this genre via weapons featuring shorter than 16-inch barrels sans any rifle stock; only the buffer tube is protruding from the rear of the receiver. The AR buffer tube soon proved an advantage on these large pistols for numerous reasons. The buffer tube appendage was adapted to accommodate various types of braces to aid in supporting large, non-typical handgun forms.

The author tested the GUARD PSB 9mm model pistol with brace, featuring Magpul MOE pistol grip and KAK Shockwave Stabilizer and Tube. The 8-inch, 4140 medium taper barrel and 7075-T6 billet lower and forged upper contributed to a weight of 5 pounds. Dimension of the GUARD is 24 inches.

CMMG wisely decided to utilize GLOCK magazines with the MkG and not some proprietary feeding device. GLOCK magazines are known for their reliability plus are abundant and reasonably priced. I know what most of you are thinking. Yes, the GLOCK 33-round stick magazines are a perfect companion for the CMMG MkG GUARD. The MkG GUARD accommodates the GLOCK magazines with a bolt-catch linkage (patent pending) that locks the bolt rearward after the last round and is released simply by pushing an oversized released button. More attention to detail is found with the integrated, oversized trigger guard and a flared magwell machined into the billet 7075 aluminum lower.

The CMMG 9mm GUARD comes threaded in the popular 1/2-28 9mm caliber suppressor pattern. As we know, a 9mm is the perfect candidate for suppressor use considering that most of the 147 grain loadings are subsonic. CMMG offers an optional Action Tuning Kit for the MkG GUARD that allows you to adjust the action for either light loads, hot loads or suppressor use via a simple method of adding weight to the bolt carrier.

Many will question the utility of employing a pistol cartridge in a rifle-sized pattern weapon. Why not just use a rifle round? Some would argue that most engagements happen well within a 100-yard range, especially in a civilian setting, and that handling and reliability play more of a factor in quick, reactive engagements than specific caliber used. Also, less experienced shooters will find the lower recoil pulse (especially with the CMMG MkG) and muzzle blast of a shoulder-fired pistol caliber easier to manage, which often times will translate into better accuracy potential. Will a rifle hit with more authority than a 9mm? Yes; however, the advantage of carrying a handgun and pistol brace carbine using the same, easy-to-acquire and relatively inexpensive ammunition and magazines should not be underestimated. Not to delve off into worst case scenarios, but too many people are stocking up ammunition, food and weapons in these times of worry to totally discount the sentiment.

The Vortex Razor AMG UH-1 is Vortex’s entry into the holographic red dot sight genre. The UH-1 features Vortex’s patent pending FHQ (Fusion Hologram) Technology and Armor-Tek coatings for lenses. A USB port allows for recharging with certain battery types.

Many will turn to the 9mm CMMG MkG GUARD for the reduced recoil and muzzle blast represented in lieu of the increasingly popular short-barreled pistol brace weapons chambered in 5.56mm, 6.8 SPC or 7.62×51.

A Vortex Razor AMG UH-1 holographic was mounted in support of T&E. The Vortex UH-1 is Vortex’s entry into the holographic red dot sight genre. The UH-1 features Vortex’s patent pending FHQ (Fusion Hologram) Technology and Armor-Tek coatings for lenses. Even if the window is shattered or is partially obstructed by mud, snow or rain, it can still function. As long as the operator can see through any portion of the window, the entire reticle pattern remains visible on the target. The interior chamber of the optic is Argon gas-purged. Vortex has addressed eyepiece glare, a problem with some other holographic red dots. This assists in efficiency in low-light use. This feature is combined with Vortex’s innovative Fusion Hologram to provide a clear reticle in a variety of lighting conditions with 15 brightness options.

The Vortex UH-1 holographic reticle has a (1) MOA center dot, surrounded by a larger circle. There are hash marks at the 9:00, 12:00 and 3:00 positions for additional sighting reference and finally a small triangle in the 6:00 opening that is specifically designed to be a CQB sighting reference to account for bore-to-sight, off-set at ranges 7 yards and in. The Razor AMG UH-1 is designed to have a lower 1/3 co-witness with standard iron sights. Vortex has moved all the electronic components for the holographic sight into an enclosed and integrated base. The company calls this “Quantum Well Technology.” The Razor UH-1’s external surfaces are non-glare, and the lenses have anti-reflective coating. Another important and often overlooked advantage of the holographic sight is that the projected reticle is visible to only the operator.

Vortex has addressed battery life for the Razor AMG UH-1 via integrated on-mount charging capability. While a lithium CR123A battery gives a respectable 1600 hours of life, with a built-in, 14-hour cut-off if the UH-1 is inadvertently left on, rechargeable LFP123A batteries can be serviced with a USB cable without even having to remove the sight from the weapon. These batteries offer 800 hours of use between recharging. Anecdotally, the battery is placed transverse in the Razor UH-1 to avoid stressing the contact springs during recoil.

An assortment of both Federal Premium self-defense JHP and FMJ ammunition was used while evaluating the CMMG MkG 9mm GUARD including Hornady Custom 115 grain XTP, Federal Premium 124 grain Hydra Shok, Winchester 147 grain, SIG SAUER 115 grain FMJ and V-Crown JHP. Firing was at a relatively steady pace with the MkG on plate racks, dueling trees and other drills. The CMMG GUARD had no issue digesting JHP-profile bullets. This is an important issue as LE agencies and civilians use expanding ammunition to limit over-penetration in CQB situations, not to mention to increase terminal effectiveness.

CMMG MkG 9mm GUARD AR pistol is a compact companion.

Drills around barricades and vehicles had the CMMG MkG/Vortex Razor combo showing its merit. After all, the MkG pistol is a 5-pound, AR-pattern weapon with a short barrel which is known for excellent ergonomics and handling. This mated well with the holographic Vortex Razor UH-1 advantages of wide field of view and head’s-up display reticle projection that fighter pilots use. It creates an accurate image of the aiming reticle even in poor-visibility conditions like rain, snow, darkness or cloud cover and no matter where the shooter’s eye is located. The Razor UH-1’s housing disappears, and the reticle just floats superimposed over the target. The small 1-MOA dot in the center is easily seen in the brightest sunlight thanks to 15 adjustment levels.

It was surprising how simple it was to shoot accurately while moving with the MkG. This is surely a result of CMMG’s Radial Delayed Blowback (RDB) operating system managing recoil as designed and use of the Vortex Razor UH-1 optic. For comparison’s sake, a blowback 9mm AR was brought to one of the range sessions. CMMG’s representations about lighter felt recoil and being able to control the MkG during rapid strings of fire were borne out.

The CMMG MkG 9mm GUARD proved accurate and durable during testing at Echo Valley Training Center with nearly 550 rounds fired over multiple range visits. The GUARD delivers on its promises of reduced recoil and muzzle climb; this makes a user more effective in engaging targets in a rapid fashion. The ability of the MkG GUARD to interact so well with the GLOCK-chambered 9mm handguns has to be viewed favorably with so many departments already issuing G17 or G19 handguns to their personnel. This will no doubt also influence private citizens to consider it a viable option to combine CMMG MkG and GLOCK weapons.

The inherent familiarity most have with the AR platform, not to mention the GUARD’s ergonomics, validates CMMG’s decision to continue to enhance it via caliber expansion. There are many situations in which a 9mm-braced pistol AR-type weapon could be very advantageous. The increase in terrorism and acts of mass violence means that something with more range than a handgun is a welcome addition to one’s personal armory. The compact stature of the MkG 9mm GUARD allows for easy transport in a smaller-than-expected package. In designing and building the MkG 9mm GUARD, CMMG has taken a proven weapons system and made it better. The CMMG MkG GUARD places real tactical power in a compact, accurate and reliable package.



Vortex Optics

Echo Valley Training Center


Black Hills Ammunition

Federal Premium

Hornady Mfg. Inc.