November 12, 2021
By Michelle Hamilton, Field Editor
Ask anyone who has been in the AR scene for any length of time, "who makes the best quick detachable (QD) mount on the market?" the most likely answer will be LaRue. LaRue Tactical is a Texas-based company with roots reaching back to 1980 when Austin Precision Products, Inc. was founded by Mark LaRue. The company was originally dedicated to servicing the Semi-Conductor industry via its ability to manufacture highly complex products to exacting tolerances.
However, fate was to lead the company to greater things when they were approached by a specialized US military unit and asked to design a QD scope mount for their specialized needs. Mark agreed, and in an amazingly brief amount of time a scope mount for the M4 carbine went from concept through at least four generations, to mass production. It was subsequently tested and then fielded in combat in both Iraq and Afghanistan, and many more designs followed leading to LaRue Tactical being formed.
Down through the years, LaRue has become synonymous with "quality" and "precision". They are known for making great products, including complete rifles in a variety of calibers and sound suppressors, for the avid shooter, especially when speaking about America's favorite rifle, the AR-15. This is why, when I was approached by Senior Field Editor (and friend) David Fortier about doing some Test and Evaluation work on Mark's products, namely their 2-Stage MBT trigger and Q.D. Cantilever MRO mount, no other word existed in my vocabulary other than "absolutely". In this article, I’ll examine the MRO mount.
The mount Mark sent me is the LaRue Tactical Model 849 (LT849 Model number), which is a quick-detachable, cantilever mount made for Trijicon's MRO optical sight. The mount height is identical to the factory MRO (and my personal favorite height) mount, which is a lower 1/3 co-witness. Lower 1/3 co-witness means that it places the users iron sights (be it fixed or folding back-up iron sights) in the lower 1/3rd portion of the optic’s Field of View, making both the optic and iron sights easily usable with little obstruction.
The cantilever mount’s design and purpose is twofold as well. It places the red dot as far forward as possible, allowing for optimal field of view, without sacrificing accuracy or zero retention which may result from placing an optical sight on a non-monolithic free-floating rail system on an AR rifle. From my experience, another advantage to the LT849 is it allows the user more room to use accessories such as optic multipliers (magnifiers), due to the optic being shifted further forward.
The mount came well packaged with everything needed to install the MRO optical sight to the mount, and the mount to the firearm. LaRue was even thoughtful enough to include a small vile of Loctite, proper hex head wrench and proprietary cam adjustment wrench (nice touch guys), although I used my own Loctite 243 on the project, along with T handle hex driver. One minor concern I had is with the instructions. While simple and straightforward, they lack torque specifications on the installation screws interfacing the mount with the optic. While Trijicon does include torque specs in their instruction manual (12 inch pounds of torque), I believe a brief refresher somewhere in the LaRue installation instructions would be beneficial.
While excellently executed and designed, the lack of real-estate on the mount doesn't lend well to the use of torque measuring devices. This means user discretion is paramount in proper installation without damage to either piece of equipment. In instances such as this, I typically use the "two finger" method of installation. With this, application of a small amount of Loctite 243 to each supplied screw, threading it into place snug. Once all 4 screws are snug in place, two fingers are used to tighten the screws into place, using a "T handle" driver. This helps prevent inadvertent damage from excessive torque on the threads. Remember, this is an interface between a threaded aluminum housing and steel screws.
Installation to the rifle was effortless and required no adjustments to LaRue’s Q.D. cam as it came from the factory. It was like the mount was made and adjusted from the factory for my billet Mega Arms upper receiver. A quick rotation of the lever locked the mount securely into place and the job was done, but curiosity took over. Using the proprietary cam adjustment wrench supplied, I did work with the rail fitment adjustments. They were effortless, smooth and a little turn goes a long way. Basically, don't get carried away with the adjustments.
Once installed, the mount and optic combo looks sleek and slim. It is as visually pleasing as it is rugged and durable. The anodizing work is deep, rich, smooth and flows well over all surfaces. There are no "rough" spots, thin spots or any bare metal showing through. The finish is so well done and clean that it is hard to imagine it being anything other than anodized black, all while zero residual machining marks remain on any surface. A personal concern of mine, especially when involving firearms that may be used for a defensive role is weight. The factory Trijicon product weighs in at 1.78 ounces and while quality, is a more permanent fixture, as it lacks any Q.D. features. The LaRue LT849 weighs in at just a fraction more at 2 ounces even. Out of the premium quick-detachable mounts I've studied, it is the second lightest offering on the market (that I know of), only being beat by the Scalarworks and their skeletonized lightweight mounting system weighing in at 1.51 ounces. While the Scalarworks is lighter, I feel the LT849 is a more robust mount and would be more likely to survive constant and consistent abuse.
On the range, the LaRue LT849 provides the user a less obstructed peripheral view than that of the factory mount. The sleeker, thinner profile and smaller footprint is most noticeable during use when transitioning from target to target. This stood out to me as I was freshly switching from the boxier factory mounting system. LaRue is famously known for commenting on their mounting systems ability to retain zero, even after being removed and remounted onto the base rifle. So, I brought two extra boxes of Hornady Frontier 5.56mm NATO match, utilizing their 55-grain Hollow Point Boat Tail (HPBT) projectile, when I hit the range to zero the optic. After a quick zero and initial 5-shot group, I put LaRue's claim to the test. A total of five, 5-shot groups were fired at 50 yards (my typical zero distance for a red dot), with the mount being removed from the rifle and reinstalled after each group was fired. The LT849 did not disappoint, with maintaining zero from first to last and no noticeable shift in point of impact.
From initial inspection to walking off the range, all experiences with this product were positive. I find them lightweight, sleek, petite but strong enough for anything that can be thrown in its direction. Using other premium quick detach mounts, I am most impressed with their cam locking design and how well-designed the locking lever is on their mounts. The fit, finish and performance provided in LaRue's products easily places them at the top tier of quick detach mounting systems for all premium optic offerings on the market. While I would have liked to have seen torque values offered, a simple flip through Trijicon's manual will provide that for the user, and it is their optic after all. Overall, this is an absolute bullseye for "the dead center of precision". MSRP on the LaRue LT849 MRO mount is $141. You can find out more about this mount, and other LaRue Tactical products HERE.
If you have any thoughts or comments on this article, we’d love to hear them. Email us at FirearmsNews@Outdoorsg.com.
About the Author:
Michelle Hamilton has a Bachelor’s degree in Criminal Justice/Homeland Security, is a serious student of wound ballistics, military history, small arms design and manufacturing and is a competitive shooter.