Blackhawk! Rail Mount Thumb Rest: Get A Grip On Your AR-15

One of the neatest things I saw at SHOT Show 2013 costs less than $20. And no, it didn’t involve dark alleys behind Caesar’s Palace.

It has no electronics, lights or knobs and it doesn’t even explode.

It’s the Blackhawk! Rail Mount Thumb Rest for the AR-15. This nifty little piece of gear radically transforms your grip. Since it’s rail mounted, and the thumb rest is off-center, you can use this in several different locations depending on personal preference and other gear you have on your rifle.

Here’s the Blackhawk! Rail Mount Thumb Rest shown with the Blackhawk! Vertical Grip. They play well together.

Think of the Blackhawk! Rail Mount Thumb Rest as a shelf for your thumb. No, your thumb is not likely to get tired and need a shelf on which to rest. The value of this piece of gear is that it provides stability and consistency. While technically your thumb does rest on the shelf, the stability comes from the web of your hand, between your thumb and index finger, wrapping around the rear edge of the thumb rest. So right off the bat you have extra vertical stability without having to wrap your hand around the hand guard or rail.

Perhaps even more important is the consistency factor. As your support hand now has a fixed place to go, you achieve the same grip and location every time you mount the rifle. No muscle memory required and you’re never gripping the forend slightly in front of, or behind, the location where you last supported the rifle.

The thumb rest is a rail mounted piece of gear, so you have to upgrade those plastic hand guards if you have them. On the rifle shown here, I’ve already added the Blackhawk! AR-15 Carbine Quad Rail Forend, so it’s ready to go. The big advantage of the rail mount for this component is that you can place it wherever you want. Back close to the magazine well, or way out front like the 3 Gunners do.

Let’s take a closer look at how the Blackhawk! Rail Mount Thumb Rest installs and the ways you can use it.

Blackhawk! Rail Mount Thumb Rest Installation

The Blackhawk! Rail Mount Thumb Rest is a two piece assembly with a main body that hooks over one side of the rail. A separate support piece mates to fasten to the other side of the rail. Just be sure to line up the bolt channels with the grooves in the rail.

The thumb rest comes with two hex bolts and two nuts that inset into the main body. Just run them through the support piece and into the inset nuts. Notice that the shelf can me mounted high or low relative to the rail horizontal center line. I’ll talk more about that in a minute. Tighten things up and you’re good to go. Once you use this for a while and get the placement you like, re-mount the bolts with a little Blue Loctite so it won’t come loose under recoil.

Since the thumb rest is offset relative to the center line of the rail, you can mount this in different ways. It goes without saying that the thumb rest is ambidextrous.

	Here the thumb rest is mounted with the shelf in the high position. It’s shown with a Blackhawk! Rail Mount Vertical Grip.
	The high shelf mounting option is great if you normally like your hand to wrap over the top of the rail. It will place your thumb almost level with the top rail so your thumb can slide onto the top of the hand guard.
	Or, you can flip the thumb rest upside down so the shelf is low relative to the rail center line.
	If you’re using a vertical grip, this will put more of your hand on the grip post as compared to using the post as a support for your fingers. Notice this location keeps your thumb low and aligned with the bore.
	The Blackhawk! Rail Mount Thumb Rest works just as well without a vertical grip. I liked it in the high position this way.
	Here’s how it looks mounted in the high position with no vertical grip.

One last thing. If you like a vertical fore grip, you might be able to mount this on the opposite side of the rail. The idea would be to grasp the vertical grip with your thumb on the opposite side. The shelf could be placed in such a way to line you up with a rear-activated light mounted on the same side. The fore grip I’m using here didn’t sit quite right with that configuration, but depending on what you have, it might work for you.

Now that I’ve taken this to the range a few times, it’s become a welcome addition to the Blackhawk! custom AR I’m building. This piece will stay. And in case you’re wondering, after the photos were taken, I settled on the high mount option with a short vertical grip from Blackhawk!. We’ll talk about that more in the next article.