Review: Upgrading The SCAR17S With KDG

    It is not a secret that I am fond of my SCAR17S. The gun is just magic. With 168 gr BTHP I can put it in the hands of any non-shooter and they can hit steel at 200-300 yards with ease. My friend Greg saw the light at the 2015 FNH USA 3Gun Match when he tried my SCAR17S. Shooting off the bow of a small boat, he hit the 400 yard steel on the first shot. He even said “this is magic”. I just point it at targets and it hits them. So how could I improve this perfect weapon system? Kinetic Development Group Upgrades.

    First up is the rail system. I have been running the Midwest Industries SCAR Rail extension since August 2013.


    I like using the extended hand guard as I like to control the muzzle when I am shooting close range targets like the ones at the FNH USA 3Gun matches.




    The Midwest Industries rail has its pros and cons. I liked it for the receiver height rail so I could mount my off set front sight as far forward as possible, but I rarely used my offset sights for accurate shots. The taller rail also made it harder to get my thumb over the bore.



    The side rail made a nice ledge to rest my thumb. However the picatinny rail made this rough to hold. Personal preference I ended up using Magpul handstop kits and ladder rail covers to smoothen out the MI rail.



    While the MI SCAR rail served me well, I have moved on to the KDG MREX 6.5″ MLOK rail.  With the lower top rail, I can mount lights or lasers without interfering with my sight plane.



    A higher priority was the weight savings and how the hand guard feels in my support hand. The MREX only adds 3.7 oz to the gun whereas the MI rail added 8 oz; more than double the added weight of the MREX. Looking at the specs of the MI MLOK rail, it is lighter than my old MI rail but only by 0.5 oz. It adds 7.5 oz to the SCAR. The weight savings is instantly noticed with the KDG MREX when picking up the SCAR17S and supporting the front end.

    The MREX rail is narrower than the MI hand guards. I can get my thumb over the bore and grab most of the rail. I feel like I am in more control of the barrel with the MREX.

    DSC_0328 DSC_0332

    The MREX replaces the side and bottom rails on the SCAR weapon system. With the side and bottom rails removed, you have a smooth contoured handguard. There are holes along the side in case the user wants to add rails, however I have never mounted anything that far back on the factory black polymer side rails. When I did mount something on the side, it would be near the front like in the photo above of my MI rail equipped SCAR. The bottom rail can be handy but again it is something I rarely used. When shooting Heavy Optics in FNH USA 3Gun matches, I cannot use a bipod. If I did, it would put me in Open Division. Shooting FNH USA 3Gun matches have helped push my skills and I can confidently hit targets out to 400 yards in rather short amount of time without the need for a bipod. So having rails on the bottom was just added bulk and weight I don’t need.

    Using the KDG Kinekt 7 slot rail, I can mount my SureFire Hellfighter on the bottom.


    HF Kinekt


    Another KDG upgrade is the rear single point QD mount. I had originally modified my lower receiver using an Impact Weapons Component Mount and Slot QD mount. Which required drilling a hole in the polymer and installing the QD mount. While this worked, I found that I was routinely having to re-tighten the mount. Kinetic Development has one machined out of aluminum and can be attached to either side of the upper receiver.



    The front QD mount by KDG is a little redundant if you are running the MREX rail, however it does work well as a indexing thumb rest. It is also ambidextrous and replaced the old snap hook loop attachment points behind the gas block.



    The next major upgrade is the KDG SCAR Adaptable Stock (SAS) Kit. It is a Magpul ACR stock on a metal adapter. At $299.99 it is not cheap but if you want a stronger slimmer stock, it is not actually that expensive. The ACR stock alone costs around $160. Which makes the metal stock adapter/hinge cost around $140. Which is actually cheaper when you consider the cost of similar upgrades. Handl Defense has a metal stock hinge upgrade for the factory SCAR stock and it costs $180. VLTOR’s AR stock adapter for the SCAR is $169.95. With the KDG SAS Kit the stock is factory installed onto the metal adapter.

    The ACR stock is slimmer than the SCAR stock and a little bit shorter when fully collapsed. The SCAR stock is fine but feels somewhat hollow yet bloated at the same time compared to the ACR stock.DSC_0309

    The ACR stock has a Magpul QD cup that you can install on either the left or right side. I prefer having it on the right side for when I sling the SCAR17S with a two point sling.

    The adjustable cheek riser is more pronounced on the factory SCAR stock than the ACR stock



    The 6 position factory stock can’t beat the 7 positions of the ACR stock.




    The butt pad is shorter on the ACR stock but not noticeable when shouldered.DSC_0314


    While purely a cosmetic issue, replacing the SCAR stock avoids the infamous Ugg Boot resemblance.




    The SCAR stock and ACR stock both have storage compartments for 2xCR123 batteries. The factory SCAR stock is behind the butt pad.




    The ACR stock battery storage is in the cheek rest behind the hinge.



    One added benefit to the KDG ACR stock adapter is the threaded hole. You can use a set screw to minimize any play the adapter will have with the SCAR receiver.  You can also see the stock hinge mechanism. When folded, the factory SCAR stock is held in place with the brass deflector. The ACR stock is held in place with the detent built into the hinge.



    One last note about the KDG ACR stock adapter, I can swing the stock from folded to deployed and it snaps in position. The factory SCAR stock could not do that. I would have to press the stock catch when deploying the stock, otherwise I risk damaging the stock catch.


    The KDG MREX rail and ACR stock make the SCAR not only look leaner but feels meaner. The rail is light and easy to grasp and control the barrel. The stock is solid and the metal receiver adapter is even more solid on the SCAR receiver. I am excited for these upgrades and will be testing it soon at a local two gun match.

    Nicholas C

    Steadicam Gun Operator
    Night Vision & Thermal Aficionado
    Flashlight/Laser Enthusiast
    USPSA competitor

    Any questions please email him at [email protected]