Where To Mount a Tactical Light On An AR15

in For Rifles, Gear Reviews
Streamlight Protac 2.0 Tactical Light mounted on an AR15

Estimated reading time: 8 minutes

The boogie man usually comes in the dead of night. Consider your AR naked if it isn’t equipped with a tactical light. When installing a tactical light on your AR15 the idea is to make activating the light intuitive, simple, and a no-brainer. In real-life use, you need to focus on operating the rifle. Not how to turn on or turn off your tactical light.

What To Look For In A Weapon-Mount Light

The features I look for in tactical light are simple. It needs to be lightweight, waterproof, and rugged. If I dropped the light, I expected it to continue to work. High lumens are a must. My minimum is 1,000 lumens, which can create a high-noon-like condition in pitch-black spaces. Don’t under estimate the blinding power of a strong blast of light. It could disable a bad actor just long enough for you to get the upper hand. I’ve come to appreciate lights with a rechargeable battery. Rear activation button and pressure switch compatible, is a plus. Easy mounting to an AR15 is also a must. 

Streamlight ProTac 2.0 Rail Mount tactical light
The Streamlight ProTac 2.0 light is rugged, uses a rechargeable battery, and throws 1,000 lumens of light.

A tactical light that checks a lot of the boxes is the Streamlight ProTac 2.0 Rail Mount. Your list might be different for a weapon-mounted light, but the same rules apply when mounting it.

Left Or Right-Handed?

There are a few variables when mounting a tactical light. One variable is whether you are left or right-handed. A second is how you plan on activating the light; via a pressure switch or pressing the button at the end of the light. The length of the gun barrel and the length of the rail are other variables. On short-barreled guns, like an AR15 pistol or SBR, there might not be room to mount a pressure switch. Your only option is to activate the light with your support hand thumb. Let’s look at some of the basics when installing a tactical light on an AR. Then we will look at how these variables affect tactical light placement on your AR.

Available on GunsAmerica Now

https://gunsamerica.com/listings/search

Tactical Light Mounting Basics

Shoulder your AR15 in your normal off-hand shooting position. Notice where your support hand grasps the rail. You will want to mount the tactical light slightly forward from your support hand. Make sure that the lens is behind the muzzle device. If you use a muzzle brake, burning gases are diverted to the left and right of the muzzle. If the tactical light is in the way of that blast the light will get the full brunt of that concussion force which might rattle the light useless. The lens will get some carbon buildup when shooting and that’s expected, so make sure you clean the lens when you clean your rifle.

Make sure your light is compatible with your rail, so that means a Picatinny rail, M-LOK, or KeyMod design. You might need to buy an adapter as the interface between the tactical light and the rail. Midwest Industries, Magpul, and other manufacturers offer 45-degree and 90-degree offset light mounts that can tuck the tactical light into the rail and make operating the light more comfortable. The offset can position the light higher, lower, or closer to the rail so it is easier to operate the light.

Tactical light mounted to MLOK rail.
Remember to keep the light clear of the muzzle device and the button on flip-up back-up sights.

If you run a set of BUIS sights, make sure you can access the button to flip them up when needed. Now that you know the general locations, let’s go back to the type of light you will be using.  

Thumb Activated Tactical Lights

If you decide on activating the tactical light with your thumb, then you need to mount the tactical light so it can be turned on and off with the thumb of your support hand. For a right-handed shooter that means mounting the light on the left side of the AR between the 9 o’clock and 11 o’clock positions. If you are left-handed then the light should be placed on the right side of the AR in the 2 o’clock to 3 o’clock positions. 

thumb activated tactical light on AR15 with a quad rail
If you are righted, a mounting option is on the left side of the AR15; here the Streamlight is mounted at the 9 o’clock position of a quad rail.

An exception to this can be if you run a vertical grip. A vertical allows the support hand to form a fist around the grip which places the support thumb on the opposite side of the AR. So if you are right-handed and using a vertical grip an option is to mount your thumb-activated tactical light on the right side so your support hand thumb has easy access to the light’s activation button. The reverse is true for left-handed shooters.

tactical light and vertical grip on ar15
An alternative mounting position for right-handed shooters using a vertical grip is to place the tactical light on the right side of the AR15; when you grasp the vertical grip your support hand thumb can easily activate the switch.

Pressure Switch Activated Tactical Lights

To determine the mounting location for the remote pressure switch, shoulder the rifle in your normal off hand shooting stance and look where your support hand thumb most naturally falls on the handguard. If you use a traditional cupped hand hold with your supporting hand, then the 9 o’clock position is a good option for you right-handed shooters. That would be the 3 o’clock position for you lefties.

streamlight ProTac 2.0 mounted to Springfield Armory saint victor mlok rail
The Streamlight ProTac 2.0 tactical light is mounted to Springfield Armory Saint Victor with an M-LOK rail.

If you use a bore over or thumb in line grasp then the 12 o’clock position is the place to locate the pressure switch. This is my preferred location for the pressure switch since I can activate the light shooting left-handed or right-handed. 

Cable Management

You will need to tie up loose ends, namely the excess cable cord. A dangling loop can snag on your environment and ruin your day. Zip ties looped through the rail slots keep the cable secure, and they work just fine. Tighten the zip tie and cut off the excess, then rotate the zip tie so the sharp edge from the cut is inside the rail and away from your hand. Some tactical light manufacturers include zip ties in the box. 

zip tie a pressures switch to an Ar15 rail
A zip tie can secure the pressure switch cable to an AR15 rail.

The Magpul Wire Control Kit (WCK) does a nice job of squaring away all those loose ends when you run an M-LOK rail. The WCK assemblies are M-LOK-compatible allowing you to route cables however you need: straight, at 90 degrees, or at 180 degrees. You can also pop out the assemblies and reuse them if you reconfigure your setup.

Magpul Wire Control Kit securing light cable
The Magpul Wire Control Kit does a nice job of squaring away dangling cables from a pressure switch.

Strike Industries M-LOK Cable Management Covers are another option. You can route your cable alongside the rail, across to the other side, 90 degrees or U-shape. These covers are low profile and textured.

READ MORE: AR15 Trigger-nometry: Instant Accuracy Boost

Strike Industries M-LOK Cable Management Covers
Strike Industries M-LOK Cable Management Covers add a positive tactile feel for your support hand while organizing and storing excess cable from a pressure switch.

Do You Need A Tactical Light On Your AR15?

If you use your AR15 as a defense weapon, adding a tactical light is a smart move. We never choose when evil gives us a visit. Many times it is at night and a light helps identify whether it’s a bad actor at the back door or a raccoon.

*** Buy and Sell on GunsAmerica! All Local Sales are FREE! ***

Leave a Reply

Your email address will not be published. Required fields are marked *

  • jerry September 6, 2024, 10:56 am

    I must disagree. Where you mount the switch is secondary to the position of the light’s beam. If you shoot right-handed you want that light either under the barrel or on the right side. 4 or 5 o’clock is ideal. Why, you ask? Because if any part of the beam hits the front sight or even the muzzle brake, you will be blinded by the reflection. The only part of that beam you want to see is the part that shines on the target. Stay safe. j

Send this to a friend