Originally Posted on The Mag Life Blog October 16, 2023 • by Jason Mosher

Do you have a light mounted to your AR-15 rifle? If not, you should. Especially if you plan to use your rifle for home/self-defense. Most of us go to the range during the day, compete during the day, and train during the day. This makes it easy to forget about the need for lights. Waiting until you need a light is the wrong time to realize you don’t have one.

Deciding you need a light is the first and easiest step. Selecting the light is a little harder. There are lots of options with brands, sizes, battery types, mounting, etc. One of my favorite brands of lights is Streamlight. I have used them in the field and at home for years.

The ProTac light comes with a pressure pad attachment. [Photo: Jason Mosher]

When you are buying a light for a weapon, you want that light to be reliable and durable. Streamlight accomplishes both at a reasonable price. The TLR-1 is probably the most used light for handguns by law enforcement in the US. I’ve seen them get smashed, run over, and submerged in water countless times. So far, I have never seen one stop working.

The ProTac series of weapon-mounted lights is the equivalent for rifles. They come in several sizes and have a few choices for mounting and operation. Where you mount your light, the type of activation switch you choose is really up to you. We will look at several options available for the ProTac so you can be on your way to setting up your AR-15 rifle.

Choosing the Right Size of Light

There are several sizes of ProTac weapon-mounted lights. Weight is, of course, one thing to keep in mind because the light will make your rifle front heavy. I have covered the specifications of these lights in a separate article, so I’ll just give a quick recap here. The largest ProTac light (Rail Mount HL-X Laser) has a laser built-in, so the extra size also gives you an additional accessory.

It uses a rechargeable battery or two CR123A batteries. The back of the light has two buttons, one for the light and one for the laser. If you choose to use the rail-mounted pressure pad for the light, both laser and light activate when pressed. The medium size light (Rail Mount HL-X) does not have a built-in laser. This means it’s smaller, but still uses the same rechargeable battery (Streamlight SL-B26).

From left to right: ProTac HL-X Laser, ProTac HL-X, and ProTac Rail Mount 2. [Photo: Jason Mosher]

Both lights have 1,000 lumens on the high setting. They also have a strobe setting and low power mode. You can program the lights using the 10-tap programming method. This will select if the light comes on in low power mode and that happens with a double tap of the power button.

I have my lights set so that the strobe does not come on with a double tap, but instead goes to a low-power mode. The third, and smaller ProTac light is the Rail Mount 2 Long Gun. This light runs on 2 CR123A batteries but is not compatible with the rechargeable SL-B26 battery. It is the lightest, however, and works great for short, smaller weapons.

Where To Mount Your ProTac Long Gun Light

Where you mount a light on a rifle isn’t something you think about until you do it. Should it be the left, right, or bottom of the handguard? Should the light stick out past the muzzle, be even, or sit behind it? You can mount a light on the bottom of your handguard if that’s where you like it. But this can get in the way when you grip your gun with your support hand, so keep that in mind.

Others like to mount low-profile lights on top of their rail (12 o’clock position), but this isn’t an option with the Streamlight ProTac lights. If you are choosing between the left or right side, consider how you plan to activate the light. You can push the button on the back of the light or use the included pressure pad. To use the button, you probably want the light on the same side as your support hand. If you are using the pressure pad, it can go on either.

The Streamlight ProTac is a larger light that is extremely bright, has a built-in laser, and holds rechargeable battery. [Photo: Jason Mosher]

I am right-handed so I place my lights on the left when I’m not using a pressure pad. If I am using one, I place the light on the right side of the handguard. I prefer a pressure pad on the top of my handguard because my thumb naturally falls in that position. Streamlight ProTac lights come with quick detach mounts, which is handy, but not when using the pressure pad.

The pressure pads have a separate back that screws onto the light. To remove the light, you must unscrew the back and place the original one back on. If you choose to use a pressure pad, keep in mind the pad and wire will need to be secured to the handguard. We will talk more about that in a moment.

Eliminate the Shadow

When deciding how far forward to place it, keep in mind the muzzle can make a shadow if the light is behind the muzzle. If you want to avoid this, there is a way to determine where to place the light compared to the muzzle. Place the light on the left or right side and activate the light. If the light is mounted behind the end of the gun’s muzzle, you will probably see a shadow from the barrel.

Move the light forward until the shadow disappears. This will eliminate the shadow issue, but your light lens will get clouded quickly because it’s near the muzzle break. Others prefer to mount their light just behind the barrel to keep it away from the muzzle blast. This will reduce wear on the light and keep the lens from getting dirty while you’re shooting.

There are pros and cons to both positions and people use both. Decide which one you prefer and go with it. The muzzle blast can wear on a light faster, but ProTac lights can withstand this abuse, so it really depends on which method you prefer. I like to keep my lights behind the muzzle break.

Mounting Options for the Streamlight ProTac Weapon Light

When you buy a Streamlight ProTac Long Gun light, it will come with a quick detach mount. This type of mount is attached directly to a Picatinny rail. It can be attached and removed by hand without any tools. This is handy if you need to use the light separate from your rifle. As an example, I was on a missing person call once when my primary light died, and I didn’t have time to recharge it. I removed the ProTac light from my rifle and used it for the rest of the night.

If you want to mount the light directly to your handguard without a rail, Streamlight makes an M-LOK attachment for less than $20. With this attachment, you unscrew the quick mount from the light and attach the M-LOK part to it. The two larger lights (HL-X) come with a quick detach mount, rechargeable battery, and pressure pad.

An M-LOK attachment can be purchased for the ProTac light if you want to mount it directly to your handguard. [Photo: Jason Mosher]

To use the pressure pad, you will need to use zip ties or some other application to attach the pad to the rail. I like my pressure pad to be on top of the gun, but you can mount it anywhere you want. Just make sure it doesn’t move around and the wire is not sticking out to catch on stuff. There are two small grooves on the top and bottom of the pressure pad for the included zip ties to set in. Once you have the zip ties fastened, clip off any extra and tie with a wire cutter.

Ready to try a Streamlight ProTac light for your AR-15?

If you are not using a pressure pad, the ProTac light can be installed in seconds if you have Picatinny rails on your handguard. If not, add the rail in the desired location or purchase the M-LOK attachment. The smaller light is a great size for PCC guns or as a backup light for sticking on any rifle with a rail.

I keep a smaller one in my safe so I can attach it to any rifle or shotgun I pull from the safe. I also use the largest light (with laser) and the medium-sized light. For quality, price, and accessories, this series of lights is hard to beat. You can buy a double pack of rechargeable batteries for under $25 so you always have one charged and ready to go. They charge using a micro-USB cable.

There are plenty of other quality lights on the market. Surefire, Steiner, and others produce quality products. But the Streamlight ProTac is one of the best deals I have found. If you are planning to add a light to your rifle, give one a try.