MK18 CQBR Project With Daniel Defense

MK18 CQBR Project with Daniel Defense


For those of you who follow the channel and this blog, you are certainly aware of the MK18 CQBR project that took place over the last year and a half.  After planning, purchasing, registering, assembling, zeroing, and a whole lot of waiting, a goal I had set became realized.  The MK18 was not a platform that I desired simply because elite special forces adopt similar configurations, but rather because it has been a proven CQB setup for over a decade of continuous conflict.  

The MK18 on the bench after a cleaning.

Why the MK18?  

Having owned, trained with and utilized 16", 14.5" and 11.5" variants of the AR family for over 25 years, my curiosity on the performance and handling of what is widely accepted to be the shortest and yet still reliable platform was perked by its proliferation in elite units.  

The MK18 CQBR is a fascinating development in the world of small, lightweight, compact weapons systems.  The platform was developed by the US Navy, and furthered by Naval Surface Warfare Center - CRANE.  It serves as a great reference point for any agency or individual looking for a reliable and compact variant of the M4.  Ideal for working out of vehicles, VIP protection, CQB, and a variety of other applications, the MK18 is highly effective when space is limited.  

The MK18 as it is labeled by the U.S. Military, comes standard with a 10.3" barrel.  Research and testing by the military, suggested that this barrel length, with proper gassing and buffer weight assembly, as well as an improved extractor spring/O-ring combination was the shortest, compact variant of the M4 family possible while still holding onto accuracy, reliability and bullet energy.  This was the smallest the AR/M4 family could essential get.  

Over the years the MK18 has been subject to modifications by the military.  Gas block changes, rails, as well as the optics and sights issued as part of the SOPMOD package evolved over time.  It is not uncommon to see MK18s in service sporting variable optics as well as fixed 4x ACOG TAO1NSN scopes.  

How This Project Came About.


KAC Rear BUIS
 The project began with a quality lower receiver that I would have to register as an NFA item, being that it would soon be the chassis for a SBR upper receiver group.  A Colt lower that was nearly brand new, and of obvious known quality was chosen to be the lower for this project.  After filling out the necessary paper work, the documents were mailed to the NFA for approval of a $200 tax stamp.   So began the wait.
H2 with Sprinco Blue next to MK18 Upper

Then began the slow, expensive and arduous process of acquiring the necessary parts that would bring this weapon system to completion once the stamp was approved.  Knights Armament sights were a given.  I already owned an Aimpoint M3 on a Larue mount.  A Geissele SSA was going to be the trigger of choice. The LMT Sopmod stock was not only a common feature on the MK18 but happened to be my favorite stock.  The Tango Down battle grip was comfortable, as well as common on many of the MK18s issued.  Due to the short barrel and gassing, as well as the opinions of those like Mike Pannone, I decided on the H2 buffer with a Sprinco Blue spring as well as the Sprinco Extractor spring.  The largest and most costly "part" that would ultimately make this platform what it would become was the upper receiver group.  The Daniel Defense MK18 upper receiver group was in my opinion, the most accurate and quality 10.3" barrel and was available with the Daniel Defense RIS II rail system found on the MK18s in service.  The Daniel Defense with a free float, cold hammer forged barrel was undoubtedly the first choice upper group for this platform.  

Firing MK18
When the stamp arrived, 9 months later, it was time to have the lower properly engraved.  This is another article in itself on NFA items and engraving.  After the engraving process was performed by Ident Marking, it was time to assemble the parts.  The Geissele was dropped in, the LMT stock slipped on, and the sights and optic placed on the upper receiver.  

Range day couldn't come soon enough.  When the day finally arrived, I was curious as to how accurate and reliable this new setup would perform.  Impressed is an understatement.  As some of you have seen on the video (below), the MK18 digested a myriad of ammunition brands, loads and bullet weights with ease.  The accuracy, out to 450 yards, with the KAC iron sights, impressed every member of the channel present at the range.  Over two days, and countless magazines, the platform ran without issue.  Flawless.  


2 MK18s and a pistol at range day.
I am very excited about the completion of this particular variant.  Would I recommend it?  Yes.  The compact, light weight configuration is nimble, accurate and powerful.  We completed two nearly identical builds here at the Denny Ducet channel, and both have proven to be work horses.  I would recommend the MK18 upper from Daniel Defense, or their complete MK18, to any agency or individual looking to utilize the most compact AR variant while maintaining renowned accuracy and reliability.  


The MK18 is easily becoming my go to "black rifle" (have yet to paint it).  With an effective range to 450 yards utilizing iron sights, there are no target challenges within carbine range that this short barreled AR variant cannot meet.  
About the Author: A.A.S NREMT-Paramedic, P.O.S.T. Certified SWAT Paramedic, TCCC/TEMS, Active SRT Member since 2006, 25 years of experience and training with M4/AR-15 variants with tens of thousands of  rounds sent down range out of Colt 1911, 6933, 6920, MK18 without a hiccup.