It seems that on every free-floated hand guard review I’ve written, reader Tex300BLK has weighed in strictly to ask me when I was going to test the BCM KMR rail. So I forwarded his comments to the fine folks at BCM and asked real nicely. They happily responded and asked me for my address and a few short days later, I had a 13″ KMR rail on my doorstep . . .
Billed as being invented by the “Father of KeyMod”, BCM claims that the KMR is light, tough, and strong. And sure enough, upon initial inspection, the first thing you notice is how darn light the rail is. The rail alone without hardware weighs 5.35 oz. which is basically featherweight status. Keep in mind that my test unit was a 13-inch version and that BCM offers 9- and 10-inch versiona as well for those looking to shave even more weight. Folks looking for a lightweight build should surely have their ears perking up at this point.
BCM indicates that they’re able to get such a lightweight 13″ hand guard by using an aluminum and magnesium alloy that sheds 30-40% of weight vs. pure aluminum without sacrificing strength. The full kit including rail and mounting hardware weighs in at 7.6 oz.
When I emailed Tex300BLK to tell him I had the KMR inbound, he told me that installation was fairly straightforward, but like anything, go slow and take your time. I found installation of the KMR to be easy enough assuming you have all the right tools. If you don’t, a qualified gunsmith should handle the job for you.
The kit includes not only the hand guard and all necessary hardware, but a very robust wrench to help knock off a mil spec barrel nut and replace it with the KMR-specific nut. You’ll also need the tools to remove your gas block from the barrel so you can thread on the new barrel nut.
The thing I appreciated most about this system is there’s no correlation between barrel nut torque and hand guard timing. This differs from the Noveseke NSR, Strike Industries Mega Fins, and a gang of others which require you to crank down on the barrel nut until everything fits. If you’ve read my Mega Fins review, you’ll remember that Strike includes a series of shims to assist in timing which had the less-than-desirable effect of creating an ugly space between receiver and hand guard.
The BCM system uses a solid barrel nut with a U-shaped channel cut all the way around. This channel is where the two sets of screws that hold the whole thing in place reside. No matter what you torque your barrel nut to, the hand guard will always fit tightly to the receiver, and be perfectly timed.
I’ve never independently tested it, but some people in the gun industry have told me that there’s a correlation between accuracy and barrel nut torque. That claim may or may not be a steaming pile of bull excrement, but if there’s any truth to it, the BCM KMR would allow you to set your barrel nut to your desired torque setting without worrying about having to time the hand guard in place.
Once the barrel nut is torqued using the included robust tool, the instructions suggest heating up the hand guard with a hair dryer for a few minutes to help fitment. While the hand guard is heating up, the gas block and tube are installed, and screwed in place. After the hand guard reaches optimal temperature, slide into place and install the necessary hardware.
There’s a small metal shim that sits between the hand guard and receiver to ensure that everything is timed correctly, though there’s a little wiggle room to make sure it’s perfect. Your installation experience may vary, but mine required liberal tapping with a 2×4 and a mallet. Once in place, torque the retaining screws in the order specified in the manual and you’re done.
Altogether, it’s a really fast install owed mostly to the fact that you don’t have to constantly torque and re-torque the barrel nut to get everything timed correctly. Just hit your desired torque spec, get the hand guard in place, and fit the retaining screws. That’s it, you’re done. I managed to do mine in about 20 minutes owing mostly to how slowly I went while following the instructions. I’m fairly certain I could do the next one in just a few minutes.
But don’t mistake speed of install for being indicative of a less than stellar product. Really the only bitch I have is that the finish doesn’t match the finish of my receiver. Super detail oriented operators may want to call BCM and see if there’s a way to match the finish for the two. In either case, the BCM KMR is lightweight and sturdy as hell. I was unable to loosen it or beat it up in day to day use. Installation of the rail didn’t seem to make my gun any more or less accurate, but it did give me additional mounting positions for accessories with the KeyMod sections at 3:00, 6:00, 9:00 o’clock and all the positions in between. This allows a ton of real estate for lights, lasers, grips, and kitchen sinks.
Specifications: BCM KMR 13 Hand Guard
- Materia: Aluminum/magnesium alloy
- Mounting: KeyMod interface system
- Length: 13″ length
- Weight: 7.76 oz (including mounting hardware)
- Color: Black
- Price: MSRP is $300 but you can buy direct from the manufacturer for $269.99 or, yes, Cheaper Than Dirt for $230.23
Installation * * * * *
With a good action vise and a torque wrench, you have what you need to install the BCM KMR. The company is kind enough to include the special tool needed to install the barrel nut along with the Torx wrench necessary to torque the retaining screws in place. The whole installation process is very quick and doesn’t require any torquing and re-torquing of the barrel nut to time the hand guard.
Fit, Finish, Quality * * * * *
The KMR, though light as a feather, seems to be as tough as a rhino. The matte black finish seems to be stout and I wasn’t able to easily scuff it using a set of car keys or a screwdriver. Overall, it looks real nice, and seems real strong.
Accessories * * * * *
From my keyboard commando chair, KeyMod is the defacto standard for modular accessorizing. Yes, M-Lok is a thing, and you should see a M-Lok hand guard review coming, but the world of KeyMod accessories is huge. Literally anything you want to stick on your gun can be found in a KeyMod compatible platform
Overall Rating * * * * *
It isn’t often that I’m absolutely floored by a piece of gear, but the KeyMod hand guard has done it. This thing is so light, so strong, so modular, and so good looking, that it has become my standard for all new builds. I don’t really see a reason to mess around with another type of hand guard when I can get everything I want in one package.