02 03 Airsoft Tech Talk: Kinetic Development Group SCAR MREX Rail Review 04 05 15 16 19 20 21 22 23 24 25 26 27 28 31 32 33

Kinetic Development Group SCAR MREX Rail Review

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It's no real secret that I'm a big fan of the SCAR platform. It combines AK-like reliability with updated ergonomics for the 21st century. I have a few minor quips with regard to certain design features, but one can largely blame the strange foibles of SOCOM for those. Fortunately the aftermarket industry is beginning to spool up full bore with innovative solutions to many a shooters whims and preferences.

One of the complaints directed at the SCAR platform is the handguard. I'm not a particularly big fan of full picatinny forearms as they usually offer more rails than are actually needed. The SCAR is no exception either. While not nearly as bad as some of the full picatinny rails of old (few will remember the behemoth that was the A.R.M.S. SIR System, still billeted as "The most advanced handguard in the world!" lolz...), it is far from completely comfortable too. The SCAR's forearm setup is considered to be short in this day and age too, especially in light of the extended-forearm-hold fad that is well entrenched now. Moreover, once you were done mounting grips, lasers, lights, and whatever else you desired, the SCAR's forearm was suddenly awful crowded, with limited space for your hands. Often times this comes at the expense of ambidextrous use too - as you are forced to sacrifice some grip space for this piece of kit or that.

There have been several aftermarket solutions that offered extended rail-space for just this problem for some time now. Few were what I would call ideal, however. Most simply added more rails and length (and/or girth and weight) without actually addressing some core considerations - namely, most of us don't need all of those rails. Additionally, one can shave a lot of weight and girth by offering a system that allowed for removable rails too.

The Kinetic Development Group solution...

A relatively new player to the SCAR market, but not the firearms world (the designers reputedly herald from LWRC fame), is Kinetic Development Group. Their core offering is the new SCAR MREX handguard system, which can be had in several configurations and colors. Currently offered in 4.9" or 6.5" extended rail setups. Rail attachment systems offered are either the relatively new MLOK setup pioneered by Magpul, or the "industry standard" method, which consists of a series of threaded holes for variously sized picatinny rail sections. It is perhaps interesting that they do not offer a KeyMod offering (yet). This could reflect on their confidence in the MLOK system perhaps attaining ultimate market share over KeyMod. Magpul has tremendous sway in the firearms world, so with the introduction of MLOK, you can bet manufacturers are paying attention.

For my purposes, I decided to go with the 4.9" rail with MLOK attachment system in black. I will admit that I'm not a practitioner of the extended forearm technique, nor do I really intend to become one. I've tried it many times, but it just doesn't work for me and my body mechanics. Mostly what I was looking for was a more comfortable grip versus what I was currently using in stock form. I also like the idea of covering up some of the gas block too - which obviously gets hot enough to melt nylon (and fingerprints) during extended shooting sessions.

The 4.9" MREX reportedly weighs an astoundingly light 2.5oz, which puts it among the lightest of the aftermarket handguard solutions. The lightest being the Handl Defense carbon fiber setups, which command a whopping $400+ price tag. So similar to the cycling world, you will pay more for lighter components. I do not have a scale or method of weighing this item, so I can't verify the accuracy of the printed information on KDG's website.

Retail price on the MREX rails runs around $300 shipped. This is more or less the new middle ground as far as rail prices go for the SCAR platform.

Specifications:
Full kit includes 2 MAGPUL MLOK™ polymer accessory rails, installation torx wrenches, torx screws and vibratite. KDG decal and a nice PVC patch are also included.

Yeah, yeah, who cares? Will it fit Airsoft though?

The quick and dirty answer is - yes. The fine print is: not without permanent modification. I briefly attempted to fit the MREX to my VFC SCAR Mk.16 before mounting it to my real steel SCAR just to see if it could be done. What I discovered is the VFC isn't built to the same specs as the real SCAR. It's a little wider and thicker in certain areas that make a direct drop in fit essentially impossible. Field stripping is nearly identical to the real deal, however, so this would make adapting the rail to the VFC platform a fairly straightforward process. I would estimate that it would take about 15 minutes to modify the rail enough to the point where it slid into place properly though. So it could certainly be done. It's not even an especially hard modification either. As this was my first initial test for this rail, I decided that instead of butchering $300 right off the bat, I'd run it on my real steel SCAR instead to properly evaluate it in its correct design context.

The modding to airsoft part will have to come later : )

Installation and assembly...

KDG recommends you watch a short video on their website before installing the MREX handguard. It should be noted the KDG rail does not ship with instructions, and you won't find any written on their website either. For any installation tips or techniques, you must refer to the online video. For those without internet connections, you're just going to have to wing it (but you're probably not reading this then either.)

Installation actually begins with disassembly of your stock handguard setup and removal of the barrel. You can refer to any good SCAR barrel changing guide on removing your barrel assembly for this step. Disclaimer: you do not need to wear full battle-rattle to change your SCAR's barrel.

SCAR barrel assembly removed.

It is highly recommend to use a heat gun or butane micro-torch to apply heat to the bottom barrel screw if this is the first time you've removed your SCAR barrel assembly. This is to soften the thread locking compound FN uses, and make disassembly easier. I have also had success using a soldering iron applied to the torx screw for approximately 60 seconds too. Quality tools are a must.

After removing the lower rail assembly and side rails, you proceed to tap in a pair of Delrin spacers into the sides of the receiver. These do not functionally do much other than provide a slight protective cushion for sliding the rail onto your receiver without marring the finish underneath.

There is a U-shaped bracket that you want to ensure you retain for installation purposes. This will line up with the screw-holes that have the Delrin spacers installed.

After installing the spacers, you screw the handguard to the bottom of the barrel assembly using a single torx screw. It is important that you use the provided Vibra-Tite thread locking compound before installing any screws on the rail.

The next step is to simply slide the barrel/rail assembly into place on the upper receiver. Finishing up, install the remaining four rail screws. Finally, make sure you have properly torqued the barrel retainer screws on the receiver. FN recommends that you go to 62 lbs. Again, refer to any FN SCAR barrel assembly/disassembly tutorial for these procedures.

Overall, this rail is pretty simple and quick to install. It's certainly helped along by the use of better tools though. The supplied torx wrenches are rather lackluster in utility. Most of the problem lies in the fact that they are too short, and thus provide very poor leverage. Additionally, because they are short as sin, and because Torx ends are by nature sharp, I managed to slice my palm open while attempting to unthread some of the screws on the receiver. Granted, I could have used better tools from the start, but I wanted to experience installation from the standpoint of a end-user who may not have ready access to quality tools (at least those with increased leverage.)  In the end, I was forced to use better tools anyway, as the little wrenches were hardly sufficient for the task.

Lastly: it is recommended that you shoot your rifle after removing the barrel assembly to verify zero. In my case, no adjustment was discovered to be needed after reassembly. But it pays heed to double check.

A comparison of the MREX rail mounted on a SCAR 16 to a SCAR 17 with stock handguard configuration.

Impressions...

"A night and day difference" would be putting it lightly. The MREX manages to shave a lot of fat from the SCAR's front end, while not really adding much weight at all. Most noticeable is the much improved grip surface, that while smooth, feels fantastic compared to the way the picatinny rails felt before. For those who prefer thumb-over-bore techniques, this rail will also facilitate that method better too as the overall height to the top of the receiver has been reduced as well.

I very much like the stepped down rail section in front of the gasblock. This allows accessory items like
flashlights, lasers, etc. to better clear the sight-line of any mounted optics. Some guys will disagree, and wish for a more "Mk. 20 SSR" style of rail, but I think this is a more optimal solution as it retains the useability of the iron sights and allows easier access to the gas port adjustment too. I have mounted my Surefire M951 w/Malkoff Devices LED bulb to the front 12 o'clock rail using a Haley Strategic Thorntail mount. This places the light in such a fashion that I no longer get that annoying 'shadow' from the barrel anymore.

I briefly experimented with mounting the two Magpul MLOK rail sections to come up with various light mount and grip configurations. The MLOK rails work quite well, and are very secure once tightened down. Ultimately though, I found I much preferred running the rail "slick" with no accessory attachments. I may in the future add a Grip-Stop from B5 Systems to see how I like it, but otherwise, I prefer to keep my setups relatively clean. This rail just feels so good in the hands that I hate to clutter it up.

I somewhat belatedly realized the MREX comes with two spaces for QD sling swivel attachments, so I can technically do away with my front sling mount Parker Mountain Machine QD socket to save a few grams of weight. Not a big deal, but for those who haven't made the jump to aftermarket sling solutions yet, consider that most rail setups now feature QD sockets.

During my quick range session, I did not notice the rail getting hot - even despite several magazine dumps. It did get a little warm, but not uncomfortably so. I have never really felt the SCAR gets excessively hot during shooting, however. As platforms go, it seems to shed heat fairly well. The gas block will get hot though, but that is to be expected. The MREX does a good job of protecting your hands from the gasblock, and any convenient field-expedient rests you happen to be using too (gun bag, ruck, etc.) I plan to update this review down the road and once I log more time with the rail and can fully wring it out.

In closing, I would have no qualms recommending this rail to anyone looking to enhance their SCAR rifle. Having handled most of the various rail designs out there, I feel the MREX is one of the best executed designs to date. It's secure. It's solid. It feels fantastic. And, it is aesthetically pleasing too (at least to me.) I plan to get another one for my SCAR 17S, and maybe a third for my VFC when I can bring myself to carve one up.

Pros:
Cons:



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