ProTac Rail Mount HL-X: Turn Night Into Day

Designed as a dedicated long gun light, the ProTac Rail Mount HL-X by Streamlight offers an affordable and durable light for rifles or carbines. Introduced in 2017 for shooters in a professional, competitive, or personal setting, the ProTac series provides the user with flexibility and function.

The ProTac Rail Mount HL-X is one in a series of lights that includes its predecessor; the Rail Mount 1, the Rail Mount 2, and the alternative Rail Mount HL-Xs (with laser). These different models afford the user to select the best light necessary for its application.


Its 6000 Series, aircraft-grade aluminum housing ensures the Rail Mount HL-X has a robust ability to withstand heavy usage. It features a tailcap switch control or an included remote switch allowing the operator to select between the preprogrammed HIGH/STROBE, HIGH, or LOW/HIGH modes. Included with the Rail Mount HL-X is a two-button remote switch with the necessary mounting hardware to attach it to a Picatinny/MIL-STD-1913 rail.

While each model within the ProTac line has a different light output, the Rail Mount HL-X produces 1,000 lumens (or 27,600 candela) on HIGH or 60 lumens (or 1,600 candela) on LOW. Its narrow beam has a peripheral illumination that reaches 332 meters on HIGH or 80 meters on LOW before dispersal. C4 LED technology gives the Rail Mount HL-X’s light element a 50,000-hour lifetime, and impervious to shock. In front of the optic, the light has Borofloat glass designed to withstand a high degree of heat and impact/abrasion resistance.

Different models within the ProTac line accept a variety of power sources. The Rail Mount HL-X accepts two CR123A lithium batteries that gives the light a battery life of 1.5 hours on the HIGH beam setting, or 22 hours on the LOW.


The principle mounting system is a Picatinny/MIL-STD-1913 tool less rail clamp that enables the user to mount/remove the WML without placing the hand in front of the muzzle.

The Rail Mount 2 has an overall measurement of 5.43” (L) x 1.45” (W) x 1.72” (H) and an operating range between -40 degrees Fahrenheit, to 120 degrees. With the standard tailcap, the Rail Mount HL-X has passed the Immersion Water Test (IPX7) and with the remote switch has passed the IPX4 test and is rated waterproof up to a depth of 1 meter for 30 minutes.

The Streamlight Rail Mount HL-X is only available in Black (featured).

Product Evaluation Scores:

  • CostGood (4/5): Available at a variety of secondary vendors from $99 to $163 (depending on discount/coupon availability), the Rail Mount HL-X offers Streamlight’s legacy of durable Weapon Mounted Lights (WMLs) at an inexpensive cost. The obvious market competitor would be Surefire’s Scout series of WMLs with remote light switch ($389 – $479). Inforce also offers a Gen 2 WML ($130) that does not include a remote switch, rather it is integrated into the housing.
  • Comfort Average (3/5): In addition to its tailcap switch, the Rail Mount HL-X came with a 3 ¾” pressure switch that has a 7” length of cable between it and the base of the WML. The included rail grabbing segments allowed the user to position the switch in a comfortable position (in relation to the Rail Mount light housing) where it was easily selected while maintaining a positive grip on the handguard. The included zip-ties proved critical (although not aesthetic) in keeping the switch solidly mounted, otherwise there was notable movement. Alternatively, the Rail Mount HL-X came with an adhesive pad if the user elected to use it rather than the rail grabbers. It would be recommended to Streamlight to invest in improving the rail switch design (the biggest impact to the overall Comfort score) to make it independently more secure on the rail, or for consumers to consider a switch mount similar to ones by Cloud Defensive.
  • Durability – Good (4/5): With a housing made entirely from aircraft-grade aluminum, the Rail Mount HL-X had a durability level comparable to the leading market competitor—Surefire. This ensured regardless of the WMLs position on the rifle, or situation employed, the Rail Mount HL-X held a high-degree of impact resistance. Another feature tested was the Borofloat glass by striking it and the WMLs bezel with a loaded rifle magazine 10x before rifle drills. This neither impacted the ability of the Rail Mount HL-X to function nor damaged the front-end glass or the LED element. The main housing (on both ends) had a rubber O-ring that ensures maximum resistance to moisture penetration. The most notable negative aspect of the Rail Mount HL-X’s durability was in fact the rubberized padding of the remote switch, as it immediately attracted all the range dust possible, and will likely wear out over time (as most remote switches do). Review of customer input confirmed the remote’s durability is dubious, but not the Rail Mount HL-X itself. Customers overcame the shortfalls in the remote switch by converting to the tailcap switch. A recommendation for Streamlight would be to improve the remote switch control’s durability and its wiring if at all possible.
  • Functionality Good (4/5): From a functional aspect, the Rail Mount HL-X had the ability to select between HIGH/LOW functions and STROBE thanks to its “TEN TAP” pre-programming. It was a little tricky to get the 10 clicks and select the next cycle program, but manageable. This gave the Rail Mount HL-X an added function over its competitors, which only have a single throw switch between ON and/or STROBE settings. This added functionality to use either a LOW or HIGH/LOW beam will prolong battery life at the lower power settings. As noted in the comfort aspect, the included rail switch is also an improvement over Streamlight’s competitors in that for most WMLs the switch is sold separately, or adds to the cost of the light itself. The rail mount of the WML housing was solid and the clamp maintained a secure hold regardless of rounds fired. It did stick out a little however, risking hang-ups if not noted by the shooter. It would be an improvement to the functionality if Streamlight would have either a low-profile rail mount, or use a locking throw lever to minimize bulk.
  • Weight Good (4/5): At a lightweight 5 ounces, the Rail Mount HL-X weighs less than Surefire’s M622 (7.5 ounces w/1,000 lumens), M612 Ultra Scout Light (6.6 ounces w/1,000 lumens), and its M312 Scout (5.9 ounces w/500 lumens). So, in aspect to other WMLs with variable switches, the Rail Mount 2 has a very good balance between overall weight and light output to other vendors.

Overall Rating – Above Average (19/25)

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IMG_2889I am reviewing this product as a courtesy to the manufacturer and via STL Shooting Enthusiasts, so that I can evaluate it and provide my honest feedback. I am not bound by any written, verbal, or implied contract to give positive reviews. All views are my own, and based off my personal experience with the product.

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