The Do-All DAKA AR-15
In this Brownells Build Series, Caleb demonstrates how to create a versatile AR-15 that uses one lower receiver and two different upper receivers, all neatly stored in a Magpul DAKA case. This setup delivers flexibility for different shooting scenarios and showcases premium components from Daniel Defense, Criterion, LMT, Geissele, BCM, Aero Precision, and Forward Controls Design.
What You Will Learn
Viewers will learn how to assemble a highly versatile AR-15 platform using a single lower receiver paired with two specialized upper receivers—one optimized for close-quarters (MK18) and one for long-range accuracy (Criterion barrel setup)—all neatly organized within a Magpul DAKA case.
Benefit
This build approach offers the shooter maximum flexibility and performance across different shooting scenarios, enabling quick configuration swaps with premium components, without compromising organization or carryability.
AR-15 Build Concept Overview
The idea behind this project is to build a do-it-all AR-15 by pairing a single lower receiver with two different uppers. Instead of relying on one rifle to handle everything, the dual upper setup allows the shooter to swap configurations for different ranges and shooting conditions while keeping the build compact and organized in a Magpul DAKA case.
LMT Mars-L Lower Receiver Setup
The foundation of this build is an LMT Mars-L lower receiver. This lower features fully ambidextrous controls, making it user-friendly for both right- and left-handed shooters. The magazine release, bolt catch, and selector lever are upgraded for improved ergonomics. A Forward Controls selector lever is installed for customization, and small parts like the magazine button are swapped to improve comfort and usability.
Geissele SSA-E Trigger and Buffer System
Inside the lower receiver, Caleb installs the Geissele SSA-E X Lightning Bow trigger, a highly regarded option for precision and reliability. The buffer system is the BCM MK2 Recoil Mitigation System, which provides an A5-length setup. This system minimizes differences in recoil between short barrel and long barrel uppers and works especially well when running a suppressor.
Stock and Recoil Mitigation
For the stock, Caleb uses an LMT SOPMOD design. Paired with the BCM T2 buffer, this configuration balances durability and recoil management. Together, these parts create a smoother shooting experience across multiple AR-15 setups.
Daniel Defense MK18 Upper Receiver
One of the two uppers chosen is the Daniel Defense MK18, a proven short barrel upper. This upper is configured for versatility and compact performance. The muzzle device is replaced with a suppressor-compatible option to ensure both uppers can use the same can. Additional accessories, including optics and attachments, are added to suit the intended role of this upper.
Muzzle Device and Suppressor Setup
To optimize the rifle for suppressed shooting, Caleb replaces the existing compensator with a Dead Air Xeno flash hider. This ensures compatibility with a single suppressor that can be used on both the MK18 and the long-range upper, simplifying the overall setup.
Aero Precision Handguard and Criterion Barrel
The long-range upper features a Criterion 18-inch barrel paired with an Aero Precision handguard. The slim, lightweight design of the handguard provides stability while keeping weight manageable. Its long length offers full coverage and better ergonomics for precision shooting. This combination is well-suited for distance work while still being practical for range use.
Mag Release and Forward Controls Upgrades
Small details matter in a custom AR-15 build. The mag release button is upgraded to a Forward Controls dimpled version, enhancing grip and ergonomics. Forward Controls Design parts are also chosen for their durability and improved user interface, providing a noticeable quality-of-life improvement for serious shooters.
Forward Assist Installation
Another upgrade is the Forward Controls low-snag forward assist. This part not only improves function but also provides a clean, beveled look that reduces the chance of catching on gear. While not a dramatic performance change, it represents the type of thoughtful, detail-oriented improvement that separates a custom AR-15 from a standard rifle.
Dead Air Xeno Devices and Flash Hider
For muzzle devices, the Dead Air Xeno system is chosen. A flash hider is used for the short barrel upper while a muzzle brake is added to the long-range upper. Both are designed to work seamlessly with the Dead Air suppressor system, allowing one suppressor to serve both rifles without compromise.
Iron Sights and Accessories
Finally, backup iron sights and optics are added to complete the build. SIG Romeo and Tango series optics provide reliable performance for different shooting applications. Accessories like the MDT bipod and Arca attachment add versatility for both field and range use. Together, these parts create a well-rounded AR-15 setup that covers short-range, long-range, and suppressed shooting needs.
Conclusion
This dual upper AR-15 build demonstrates how to achieve maximum versatility without compromising performance. By combining an LMT Mars-L lower receiver with both a Daniel Defense MK18 upper and a Criterion long-range upper, shooters can quickly adapt their rifle to different roles. Packed neatly into a Magpul DAKA case, this project is an excellent example of how thoughtful component selection, premium parts, and practical upgrades come together to build a highly capable AR-15.
