MK18 Clone Overview

  • Jack Collins
Image courtesy of Riot1013

If you’re a member of the military (or just a firearms enthusiast who’s been on the internet in the last few years), chances are you’ve encountered the MK18 (AKA the CQBR). It’s one of the most infamous firearms out there thanks to its heavy use by special forces units like the Navy SEALS. In this video, SDI grad Caleb Downing introduces us to his favorite SB and one of his all-time favorite firearms: his self-built MK18 clone.

What is Cloning?

MK18, MK12, M16s, and M4s (the infamous M4gery): while impressive as military weapons, getting an exact copy of a military rifle in the civilian world is effectively impossible. A real military rifle will feature select-fire controls, while any civilian variant will only allow semi-auto fire (unless you’re dropping some significant money on a fully transferable machine gun).

To be a true clone of a military rifle, you need to use as many MIL-SPEC parts as possible. That means you can’t go around just using any lower receiver on an AR variant. If you do, your firearm will become an “inspired clone” rather than a true clone.

What is an MK18?

Essentially, an MK18 is an M16 with a super short barrel. Also known as the “Close Quarters Battle Receiver” or “CQBR,” the MK18 features a 10.3-inch barrel to be exact. That makes it an extremely nimble gun that’s useful for use indoors or in vehicles. As Caleb puts it, the MK18 is a “door kicker kind of gun.”

While MK18s may be trendy among internet gun enthusiasts, Caleb warns viewers not to fall for the hype. He concludes that the MK18 is not “the best gun in the military.” In fact, he even says that you, a civilian, can build a better gun than a true MK18 clone. One great factor that the gun does have going for it, though, is that it “runs like an ape.” Regardless of how dirty it may get, the gun never malfunctions. 

MK18 Clone Overview

When it comes to direct clones of military firearms, Caleb’s MK18 is about 95% correct. The only parts that aren’t exact copies of a standard-issue MK18 are some of the markings on the lower receiver and possibly the crush washer (possibly). That makes it nearly an exact copy of an MK18, minus select fire capabilities. Oh, it doesn’t have the slots for a grenade launcher attachment, either.

In fact, Caleb’s MK18 is such an accurate clone that he got a call from the ATF after he submitted his Form 1 (required to create a legal SBR). They were checking in with him to make sure he hadn’t taken his M4 lower receiver after leaving the military, since it had the same serial number as Caleb’s service rifle. Wisely, Caleb made sure that his MK18 clone was accurate, yet compliant with regulations.

Key Specs

  • 10.3-inch barrel
  • BCMGUNFIGHTER™  Stock (to prevent lost beard hairs)
  • Aimpoint CompM2
  • Colt A2 Flash Hider
  • No silencer, although some MK18s do use them

Learn More About Drone Terms and Tech at SDI

Do you love learning about firearms like the MK18? At SDI, we can help you expand your firearms knowledge base. To learn more, check out the programs and certifications we offer.

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