The MRP starts as an eight-pound billet of aluminum. After five hours of CNC machine time it weighs just 1.47 pounds when finished. LMT offers two versions of the MRP: the rifle upper for use with barrels 18 inches and longer and the CQB (this is the one tested), which can be used with barrel lengths of 10.5, 14.5, and 16 inches. Barrels can be had in both chrome-lined and stainless-steel configurations and are rifled with a 1:7 inch twist. Because of the indexing groove cut on the bottom of the barrel extension, only LMT barrels can be used with the MRP.
Since the receiver also includes an integral handguard, the upper portion of the MRP CQB features 16.5 inches of continuous Picatinny rail. Optics, lasers, night vision equipment, lights, a vertical foregrip, and a bipod can all be added to the carbine via the rail system. LMT hard coat anodizes the upper receiver to milspec. The rail grooves are also numbered so equipment that has been detached can be quickly reattached in the same position it was last used. The numbers are in white and easily visible with night vision goggles.
My test sample came equipped with LMT’s detachable sights. The rear sight, which affixes to the Picatinny rail by means of a single thumbscrew, is adjustable for both windage and elevation. It looks very much like the detachable carry handle sight used on the M4 with the carry handle machined away. The front sight also attaches with a thumbscrew. Since I was more interested in the carbine’s mechanical accuracy, I mounted a Trijicon 1.25 x 4 Accupoint scope for the accuracy portion of the evaluation.
I did all of my shooting from a seated position using a rest on top of a cement benchrest. Because I do not have the proper licensing for a Short Barreled Rifle (SBR), I had to rely on the folks at Lewis Machine and Tool for velocities and accuracy from the 10.5-inch and 14.5-inch barrels.
As you can see from the accuracy charts, the MRP system is phenomenally accurate. Who would have ever guessed that a 10.5-inch barrel would be capable of sub-1⁄2 MOA accuracy? LMT’s MRP CQB possesses far more accuracy than most heavy barreled counter-sniper weapons. All of the groups were fired from a hot barrel without allowing for any substantial cooling time.
Switching from the 16-inch, chrome-lined barrel to the stainless steel barrel, the point of impact changed. I had to adjust the scope four inches left and add about seven inches of elevation. This change was not unexpected and for someone that anticipates using more than one barrel it would be a good idea to keep notes. After shooting my groups with the stainless barrel I reinstalled the chrome-lined barrel and found that it shot to the original point of impact. While it was boringly accurate to shoot from the bench, I also wanted to see how the carbine would perform during some rapid-fire exercises.
I set up some steel targets, about 14x14 inches at 50 yards, and was able to double tap them with ease. My friend, Frank Grijalva, accompanied me on this trip. Frank was a Fighting C.B. during Vietnam and has the scars to prove it. After being shot through the lungs and spending 14 months in military hospitals, the Navy declared him fit and discharged him. He spent the next 30 years in law enforcement. Although he is familiar with the M-16 and AR-15 weapon systems, the MRP was unlike anything he’d ever been exposed to. Despite this, he was able to hammer the steel targets with ease, making quick decisive hits. I think that he was most impressed with the scope and the glowing amber aiming point.
One thing that makes the MRP carbine easy to shoot is its SOPMOD (Special Operations Peculiar Modification) stock. LMT supplies all of the U.S. Military branches with this slick five-position collapsible stock. Its design, a wide wedge shape, provides the most comfortable cheek weld of any collapsible design that I’ve ever used. It fits my crooked face perfectly.
The SOPMOD features two watertight battery storage compartments so the operator can always have a fresh supply of batteries. It also has a rubber buttplate that makes shooting the rifle comfortable and also keeps the butt from slipping off the shoulder…even against slick nylon web gear or body armor. And unlike most of the collapsible stocks that I’ve had experience with the SOPMOD is 100-percent rattle free. LMT also supplies textured rail covers with the MRP to make handling the carbine more comfortable when the rails aren’t needed for attachments.
Lewis Machine & Tool has been building weapon systems for the military and producing parts for many American firearms manufacturers for more than 25 years. This experience shows in the design and quality of the Monolithic Rail Platform. Although the military and law enforcement have very different missions, both need a weapon that can stand up to serious abuse and sustained fire without its point-of-impact changing. The MRP is the best solution that I’ve seen to this problem thus far.
Because of the numerous configurations and options that LMT offers it’s almost impossible to quote a firm price, but the company does offer a law enforcement discount. MRP uppers are also available for separate purchase and will fit any milspec AR-15 lower.
Mike Detty is an NRA-certified rifle, pistol, and shotgun instructor. A certified rangemaster and competition shooter, Detty served as an officer in the U.S. Marine Corps and holds a degree in criminal justice from the University of Arizona.