The CMMG MkGs vs the Aero EPC

I really love PCCs. These little guns are cheap, fun to shoot, and typically use pistol magazines. I also like to compete in different PCC shooting competitions, including Steel Challenge and Action Steel. I currently have two rifles I typically turn to for pistol-caliber competitions. This includes the Aero EPC and the CMMG MkGs. I have lots and lots of time behind the two guns, and I feel confident in my ability to talk about and review the firearms side by side. 


The bottom line is that both rifles are great rifles. They shoot well, are reliable, and will both work for PCC tasks. 

Why EPC Vs. MkGs

You might ask why you should compare these two rifles. You might argue, oh, it’s because you own them. That’s true, but that’s not the only reason. These two rifles represent modern AR-type pistol caliber carbines. Both fall into this new generation of ARs in 9mm that cure some of the mistakes of previous generations. 

Both guns have a last-round bolt hold open device, both use Glock magazines, and both utilize an enhanced magazine release that’s easy to use and ergonomic. Since they both sit in this realm of the next-generation carbine, it might be tough to pick from one over the other. My intent is to provide you with the information required to pick which rifle will work for you.

The Price Difference 

For many people, the biggest difference will be the price of the rifle. That said, the Aero EPC is the more affordable option, though the cost of the EPC is tough to pin down because it varies wildly depending on the options selected. It’s not tough to buy or build one for about $800 with modern rails, Magpul furniture, and a decent stock. 

The cmmg mkgs profile
The CMMG MkGs is my go-to gamer rifle.

The CMMG MkGs is a much more expensive rifle. It’s going to cost you about double. You might find one for around $1,400 with a plain black finish, but getting one cheaper than that is tough. There is a reason why the MkGs cost more, and it comes down to the operating system. You might need to individually decide if the advantages of that system are worth the cost. 

Build or Buy 

Before we dive deeper, I will say that when it comes to the Aero Precision EPC, you can choose to build or buy. Aero is a builder’s brand, and they produce the receiver sets, the BCGs, the barrels, handguards, and more that let you build the rifle or pistol you really want. CMMG does make the internals of the MkGs available, but they tend to be harder to find, and you have all the other parts and pieces you want. 

Aero epc on ground
The Aero EPC provides a very affordable option for the PCC enthusiast.

If it comes to building or buying, the Aero EPC is easier to build but sometimes tough to find as a complete rifle. The CMMG MkGs are better if you plan to buy rather than build. 

The Operating Systems 

The biggest difference between these two rifles is the functional design of the operating system. This is why the CMMG MkGs cost so much more than the EPC. 

The EPC uses a very simple direct blowback system. It’s the most popular PCC operating system. This system lacks a locking breech and instead relies on a combination of a heavy bolt and buffer spring to keep the breech closed until the projectile leaves the barrel. This system is super common, and the economy or scale and simplicity make it quite affordable. 

cmmg bolt is similar to the ar-15 bolt on the right. the aero's bolt is on the left
The radial delayed system uses a more traditional bolt. The EPC uses a blowback-operated bolt.


The CMMG MkGs use CMMG’s patented radial delayed blowback system. The bolt looks a lot like a standard 5.56 bolt. Those lugs lock and rotate into a proprietary chamber design. This locking system keeps the breech closed without the need for a heavy spring or bolt. This locked-breech system offers numerous benefits, which we’ll discuss as we go. 


This will be a fairly short section because the guns are nearly identical. Both guns are fairly stock. The CMMG is entirely stock with parts made by CMMG. The Aero EPC is almost all stock, but I have a Magpul grip and a Mission First Tactical stock. Other than that, it is all Aero produced, from the barrel to the rail and beyond. 

aero epc against tire
The Aero EPC allows builders to make their dream rifle.

Bot guns feature huge charging handles and a magazine release that’s pressed rearward enough to work with your trigger finger. Glock mags lock differently than rifle mags, so the magazine release has to be altered to be effective. Both work and as mentioned, both guns have an LRBHO device for quick and easy reloads. Both lowers feature beveled mag wells for quick reloads, and both drop a variety of Glock magazines without an issue. 

Man reloading EPC
Both guns feature big magwells that make it easy to reload.

The small differences are the weight, charging handle, and safety. The CMMG is slightly lighter since it doesn’t need the heavy bolt and heavy buffer. It also comes in stock with a short-throw safety design, which is nice. Finally, the lack of a heavy buffer and heavy buffer spring allows the CMMG charging handle to have less resistance when operated. Those minor differences are all we have to deal with. 

Recoil and Handling 

Due to its direct blowback design, the Aero EPC generates more recoil than the CMMG MkGs. The MkGs’ locked breech helps reduce recoil. The difference is quite significant, and I’m significantly faster with the CMMG MkGs on a competitive course of fire. These courses of fire often have very small targets, and the difference in recoil means my red dot moves more between shots. 

CMMG MkGs shooting around cover
The lightweight rifle makes it easy to shoot around cover and in other awkward conditions.

With the CMMGs MkGs, I can clear a course of fire faster and often shave a second or more off. That doesn’t seem like a lot, but it means a lot when a course of fire might only last nine seconds. The difference isn’t as significant on a man-sized target, and for home defense, the Aero EPC won’t let you down. 

The MkGs and EPC don’t have a ton of recoil overall, but the MkGs have much less. It’s sort of like the difference between a dime and a nickel; a dime is twice as much as a nickel, but it’s still not a ton of money altogether. 


One thing about the blowback operation is that it’s reliable. The radial delayed design is less proven, but in my experience with two radial delayed guns, they work extremely well. Both guns score extremely high on the reliability meter. I’ve thrashed these two guns, failed to clean them, and typically shoot the cheapest ammo I can get. They don’t ever stop working, as far as I’ve seen. 


What’s the difference between the MkGs and the Aero in terms of accuracy? Not much. These are 9mm rifles designed for use at 100 yards at the very max. Neither are precision rifles, and both perform almost identically. The MkGs has a better trigger, but it doesn’t really matter within 9mm range. 

shooting aero epc
The Aero EPC has harsher recoil, but it is still a real kitten.

The CMMG MkGs series is easier to fire fast and accurately. Less recoil means less movement, which makes it easy for me to swap targets without missing a target. The CMMG MkGs is the better comp rifle, and I prefer it for competitive purposes, but I still use the Aero EPC for a variety of tasks. 

In the End 

The CMMG delivers an entirely different operating system, which ultimately results in less recoil. However, is the second difference or so worth the cost of admission? That’s up to you to decide. Both the CMMG MkGs and Aero EPC come from reputable manufacturers, and both guns offer a reliable, easy-to-use, and fun-to-shoot platform. 

Travis Pike is a former Marine Machine Gunner and a lifelong firearms enthusiast. Now that his days of working a 240B like Charlie Parker on the sax are over he's a regular guy who likes to shoot, write, and find ways to combine the two. He holds an NRA certification as a Basic Pistol Instructor and is probably most likely the world's Okayest firearm instructor. He is a simplicisist when it comes to talking about himself in the 3rd person and a self-professed tactical hipster. Hit him up on Instagram, @travis.l.pike, with story ideas.

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