Go Clone Correct with the Daniel Defense SOCOM-MK18

The Daniel Defense SOCOM-MK18 rifle started its life in development at Naval Surface Warfare Center Crane Division as the “close quarters battle receiver,” or CQBR. The goal was to provide optimum performance in tight spaces where maneuverability was of the utmost importance and the target engagement distance was generally going to be no more than 100 yards - and quite often much less.

What is the Mk18?

At its most basic, the Mk18 is an M4 with a short barrel - just 10.3” overall. The design was adopted as the Mk18 for use by USSOCOM and the gun’s profile and silhouette are pretty much synonymous with the Global War on Terror. Conceptually, the overall design isn’t new; M16 rifles in Vietnam in the late 1960s were the first to embrace the idea with the  Colt Commando or XM177.

The sacrifices you make by shortening the barrel by almost six inches from the 16” carbine length M4 configuration are far outweighed by the benefits gained in the gun’s smaller footprint. Plus, with the addition of a  suppressor, you get a gun that’s similar in size to an M4 but much quieter. This is especially important for the military when using the gun in an enclosed space like a house or vehicle.

Due to the popularity and success of the close quarters battle receiver as a standalone  upper receiver that was put onto existing M4 lower receivers, the US military began fielding complete, purpose-built CQBR guns with their own National Stock Numbers (or NSN) and their own model designations: Mk18 MOD 0 and Mk18 MOD 1.

What is a Clone Rifle?

The clone rifle concept has become incredibly popular in recent years, and the Daniel Defense MK18 is just about as close to clone correct as you can get without drilling that third pin hole and risking a stay at Club Fed.

The MK18 that Daniel Defense offers on the commercial market to civilians features the same railed forend Daniel Defense currently provides to USSOCOM (the Daniel Defense RIS II MK18), and a 10.3” cold hammer forged barrel outfitted with a Daniel Defense flash suppressor. The barrel itself is made of chrome moly vanadium steel with a 1:7 twist. It is chrome lined, MP tested, and has a milspec heavy phosphate coating.

Running the gun is a carbine-length gas system with a Daniel Defense MK12 gas block, as well as an H buffer and a milspec, MP tested  bolt carrier group with a staked gas key.

The barrel and forend are mated with a milspec upper receiver with indexing marks and M4 feed ramps. The gun is a flattop, with the entire upper and forend lined with Picatinny rail for attachment of the shooter’s preferred sights,  optics, and accessories.

The lower receiver is also milspec and has an enhanced flared magazine well for easier and faster reloads as well as an integrated QD sling attachment point at the rear. The buttstock is Magpul MOE on a milspec buffer tube.

To SBR or Not to SBR?

While the MK18 barrel length of just 10.3” is of no legal issue to the USSOCOM members using it, there are some pesky legal restrictions when it comes to civilian use. Because the barrel is considerably shorter than the legally allowed length of 16”, it means that the gun is subject to the National Firearms Act ( NFA) and must be registered as a short barrel rifle, or SBR.

Getting the Daniel Defense SOCOM-MK18 as an SBR is the most clone correct way to go, but it’s understandable that people may not want to deal with the added cost, wait time, and restrictions that come with owning an SBR. That’s why Daniel Defense has multiple options available.

For starters, you can buy just the MK18 upper receiver and slap it on any already-registered SBR lower you may already have. Or, you can put it on an AR pistol lower of your choice that may be sitting in your safe waiting to be completed.

You can also purchase the MK18 as a complete  AR pistol, and there are two options available for this. The first is a standard AR pistol configuration with a fixed buffer tube. On the end is an SB Tactical SBA3 Pistol Stabilizing Brace that offers five adjustable length positions as well as an integrated QD sling swivel attachment point.

The other option allows you to take the already small gun and make it even smaller by adding the LAW Tactical GEN3-M folding stock adapter and an SB Tactical SOB Pistol Stabilizing Brace. With the folder from LAW, you can take the firearm from 30.25” in length in its ready-to-fire configuration down to 20.75” in its folded configuration. That makes the MK18 pistol super easy to stow away in a go bag or as a truck gun without sacrificing any of the reliability.

No matter how you choose to go about adding a MK18 to your collection,  Daniel Defense has got you covered!