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m24shooter
19 September 2009, 19:43
Tango Down SFRM & SureFire Helmet Light HL1-C-TN

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The SureFire HL1-C-TN mounted on the Tango Down SFRM.

The SureFire Helmet Light has been available for several years now. It provides two arrays of different colored LEDs (three color combinations are currently offered) and a small IR strobe for IFF. It can be handy for occassions where the user may not want to use a larger and more powerful light, and/or when the user requires both hands and can’t hold a light. However, not everybody wears a helmet. To fit that need several other options exist to position the light on other equipment. Hats, MOLLE adapters, and even a headband have been produced to help out those that have the Surefire Helmet Light but don’t want to use the helmet mount.

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SFRM showing the locking latch to the right and the cross screw heads towards the bottom.

One useful place to mount the light is on a weapon. The Tango Down SFRM (Surefire Rail Mount) is a means to expand the capability of the SF Helmet Light by mating the horseshoe mounting lug with a 1913 rail. The mount is a small Pic rail mounting block with two slotted cross-screws providing tension to a clamping bar. A plastic horseshoe bracket is secured to the mount base with two small screws. Once placed on the weapon rail, the two cross screws are tightened down.

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Detail of undeside of the mount showing the cross screws.

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SFRM positioned on rail. The rust visible on the washers was a result of a week in rainy conditions and was cleaned up with CLP.

The Helmet Light is then slid onto the horseshoe base and locked on as with a standard helmet mount. When the light isn’t needed, it can be removed exactly as with the standard helmet mount by pressing down on the latch lever at the rear of the mount and sliding the light forward.

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Helmet Light locked onto the SFRM.

http://i15.photobucket.com/albums/a391/m24shooter/Tango%20Down%20SFRM/sfhlhorseshoe.jpg
Underside of Helmet Light showing horseshoe bracket.

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Battery cap removed.

The light itself is a polymer housing with 5 LEDs in the front, an IR strobe on the side, and the battery compartment on the bottom. A standard 123A cell is enclosed by a tethered screwcap. The light is watertight and a manual lockout knob is located on the battery cap. This lockout allows the user to prevent inadvertant activation of the light by twisting the knob clockwise, which is clearly marked “DISABLE.”

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The battery cap and lockout knob is seen here to the left. The lefthand toggle switch is for the IFF beacon and the primary/secondary LED toggle is to the right.

Two toggle switches are mounted on the rear of the light. They are covered by a soft, flexible boot and protected by two guards molded into the body of the light. This helps to cut down on flipping the toggles on or off by other items. The five main LEDs are located on the front of the light; three are primary and two are secondary. On the HL1-C-TN the primaries are white and the secondaries are red. The topmost switch controls these five LEDs. This is a three position switch. Up activates the primary LEDs, the middle position is off, and down turns on the secondary LEDs. A larger pressure pad button is on the side of the body that is used to adjust the brightness of the primary and secondary LEDs. This pad adjusts the brightness up through three settings of increasing output. The bottom switch controls the IR beacon and is two position. Up is the on position and down is off. Small icons molded on the guards outside of each switch indicate the different toggle positions. The primary and secondary LEDs operate independent of the IFF beacon.

http://i15.photobucket.com/albums/a391/m24shooter/Tango%20Down%20SFRM/sfhliff.jpg
View of the primary/secondary power selection pressure pad (round button with rough texture) and the IR beacon located just above the "IFF."

SureFire lists the battery life as 120 hours on the IR beacon setting, 96 hours with the secondaries on low, and primary high as 6 hours. The intermediate settings/LEDs fall within that range. It weighs 3.1 ounces with battery, is 2.2” long and 2.6” high and portrudes 1” from the rail overall.

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Secondaries on low setting.

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Primaries on low.

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Primaries on high.

I mounted the SFRM as far forward as possible on the left side of my rail. Mounted in this location, the toggles on the rear of the light can be activated with the thumb or finger of the support hand. There is a shadow from the barrel when mounted in this location, but this light is for close-in inspection and navigation as opposed to target ID or disorientation, so that isn’t a big worry. The SF light slides easily onto the mount just like the helmet bracket. The Tango Down locks the light in place and holds it fairly securely. I did smack the light on a barrier pretty hard at one point and one side of the light popped out of the mount, although it did not separate from the mount totally. I didn’t notice it at first, and continued on shooting with the light only partially mounted. It wasn’t until sometime later that I noticed it and repositioned the light securely in the horseshoe bracket. While I remember hitting the barrier (and it was a good hit), I’m a little concerned about the security of the light. I’ve intentionally tried to dislodge it since then and the only way I’ve been able to replicate it is by striking the top of the light. Hitting the light from the front, side, and bottom haven’t knocked it off. For this reason I’m thinking about putting a lanyard on the light to the rail and would recommend this for others as well. Another area of concern in the mount is the durability of the mounting screws to corrosion. I’ve had the rifle out in rain over the last two weeks (it has rained almost continuously during that time). The washers for the cross screws and the terminal ends of the screws themselves showed some rusting after being exposed to the rain. There wasn’t a whole lot of rust, but enough to be visible in some of the pictures. I used some BreakFree and a nylon brush to knock that off and the result is visible in the pictures of the mount detatched from the rail. The rust is gone, but if this is what occurred from rain in North Texas I’d be a little concerned if this were to be used in a salt water environment.

Because of the small size of the toggle switches, the user needs to be careful when manipulating them. It can be difficult to operate them, especially with gloves. The pressure pad on the outside of the light can be difficult to locate with gloves making power selection difficult. Depending on how the support hand is positioned either the thumb or forefinger can be used to switch the lights on and off. One annoying habit that I found is that the battery cap can be bumped and interrupt the contact just enough to cut off the LEDs. I’ve also found that rotating the disable knob slightly off of the fully rotated position seems to eliminate this issue. If the battery cap is pressed forward (as if you were going to rotate the cap to remove it) the contact is interrupted as well. As long as those issues are kept in mind, the light can be very useful.

The red secondary LED allows for clear observation and inspection in close, and at the higher output settings it allows some ability to make out larger objects farther out depending on the environment. I’ve had no problem seeing dark colored items out to about 15 feet in a wooded setting. The white primary LEDs allow better visiual acuity at longer range. Even at the high setting the primaries are only putting out 19.2 lumens while the secondaries at low are rated at .3 lumens. This offers a wide range of illumination that can be selected by the user to fit the needs of the situation.

Since I’ve been using the SureFire with the SFRM I’ve found that I like the capability of having the small LED lights available to augment the VLI I have mounted on the right rail. It won't be for everybody, and the user should be aware of the limitations as with any other piece of equipment. Personally I find the capabilities outweigh the liabilities and will keep the light mounted.