Follow us on Social Media
Image Alt


  /  Firearms   /  The CMMG MKGS 40 S&W is a Pistol Caliber Rifle Done Right

The CMMG MKGS 40 S&W is a Pistol Caliber Rifle Done Right

A Pistol Caliber Carbine

Pistol caliber carbines are fun to shoot and have a very legitimate place in the role of self-defense. Recently I got to get my hands on the CMMG Resolute 300 MkGs 40 S&W carbine.  CMMG built this thing right.


300 Series

The 300 series designation at CMMG means that it comes with all the bells and whistles.  The MKGS 40 S&W comes with the CMMG SV brake, has a forged 7075-T6 AL M4 type upper, a forged 7075-T6 AL lower, a CMMG RML15 M-Lok handguard, the CMMG oversized ambidextrous charging handle, a Magpul MOE pistol grip, the CMMG RipStock with 6 position enhanced receiver extension, a Geissele Automatics SSA 2-Stage trigger, and a CMMG ambi safety selector.

With the 300 series you also get your choice of 10 different Cerakote colors that is applied to the receiver, hand guard, ejection port cover, and the RipStock.

The Resolute

The Resolute designation simply means that it’s going to be one of CMMG’s tried and true carbines – a 16” gun available in 10 different calibers.

When I got my hands on the CMMG Resolute 300 MKGS 40 S&W in Bazooka Green I was impressed with the fit and balance of the gun.  The carbine is quality and the parts make sense.

Nikon SPUR

I mounted a Nikon SPUR 3MOA red dot site on the rail and found it to be on the money to 100 yards on a 6” plate with no adjustments made. Shooting steel up close it was easy to pick up the red dot on moving targets.  Shooting the CMMG with the Nikon SPUR at 100 yards was a cinch after I turned the brightness down a little bit.

The Nikon SPUR MSRP’s at $219.95 and I hope to tell you more about it soon.

Glock Compatible Magazines

The MKGS uses Glock (or Glock compatible) .40 S&W magazines.  My G35 duty magazines worked great through it as well as an assortment of KCI USA magazines that I had on hand like my 50 round drum magazine.

The Geissele Automatics SSA 2-Stage trigger was wonderful and the ambidextrous controls were seamless.

This rifle was a pleasure to shoot and very accurate.

The jury is still out for me on whether or not I’d want to give up my .223 for a .40 duty rifle based upon my lack of knowledge about ballistics but I would be intrigued to see some side-by-side comparisons on gelatins and different obstacles to shoot through.  If the decision factor is accuracy, ergonomics, fit, and appearance – this thing is a success.

Tech Specs

BARREL: 16.1″, 1:16 twist, Medium Taper, 4140CM, SBN
MUZZLE: CMMG SV Brake, threaded .578-28
RECEIVER: Forged 7075-T6 AL M4 type upper, Forged 7075-T6 AL Lower
HAND GUARD: CMMG RML15 M-Lok hand guard
FINISH: Cerakote Receivers, Hand Guard, Ejection Port Cover, and RipStock
BUTT STOCK: CMMG RipStock with 6 Position Enhanced Receiver Extension
TRIGGER: Geissele Automatics SSA 2-Stage
TRIGGER GUARD: Integrated Into Lower
MAGAZINE: Glock 22rd
WEIGHT: 6lbs 7oz(unloaded)
LENGTH: ” 32.7″(stock collapsed)

MSRP is $1,799.95

About the Author /

Heath has been a law enforcement officer in the Great Pacific Northwest since 1993 and trains as a pistol and rifle instructor for both law enforcement and civilians. He also serves as an advanced armorer on pistols and rifles. If you're looking for training or would like to contact him, he can be reached at


  • jason

    July 25, 2020

    I love CMMG. Radial Delayed Blowback makes everything run better.

Post a Comment