How to Choose a Weapon Light

A weapon light is one of the few accessories where the wrong choice is not a matter of taste: it either will not clamp to the gun, or it clamps and unbalances a pistol you used to shoot well. This guide runs the decision in the order a buyer makes it — mount, size, output, power, switching, laser.

Host and mount come first

Nothing else is worth reading until this is settled. The mount standard eliminates most of a lighting range before a single lumen figure matters.

• Full-size railed pistol — a universal clamp with locating keys. The Streamlight TLR-1 HL ships with five keys covering Glock-style, MIL-STD-1913, Beretta 90two, S&W SW99 and TSW, and SIG SAUER P320 rails. SureFire splits the job by clamp: the X300U-A uses a lever-latch Rail-Lock, the X300U-B a T-slot thumbscrew clamp, both for Universal and Picatinny rails
• Compact or subcompact pistol — usually cut for a named frame. The TLR-7 X sub is a separate part number per host: Glock 43X/48 MOS and 43X/48 Rail, SIG P365/XL, Hellcat, 1913. Streamlight states the P365/XL models do not fit the P365-XMACRO but the 1913OS versions with the #4 key do — hence the TLR-8 X G sub 1913OS as its own SKU. SureFire's XC3 Sub instead ships four rail adapters covering Glock 43X/48, Hellcat, H&K CC9 and SIG P365
• Pistol with no rail — a trigger-guard clamp. The TLR-6 is built for the non-railed Glock 42 and 43
• Long gun, Picatinny or M-LOK — check the M-LOK hardware is in the box. SureFire's Scout Light Pro mount ships with MIL-STD-1913 and M-LOK cleats on lights such as the M340C, and Streamlight includes an M-LOK mount with the ProTac Rail Mount HL-X. Holosun's RAID mounts direct to Picatinny and is compatible with M-LOK and Scout-pattern systems, though an included M-LOK mount is not stated
• Pump-action shotgun — the light replaces the forend. The TL-Racker comes in three fitments only: Mossberg 500/590, 590 Shockwave and Remington 870

Size and weight, relative to the host

The classic mistake is a full-size light on a compact pistol. It usually fits, and it usually ruins the gun. Judge these figures against what they bolt to.

Light	Length	Weight	Host
Streamlight TLR-6	2.5 in (6.35 cm)	1.12 oz (31.8 g)	Non-railed subcompact
Streamlight TLR-7 X sub	2.51 in (6.38 cm)	2.39 oz on CR123A	Subcompact, railed
SureFire XC3	2.6 in (6.6 cm)	2.65 oz (75 g)	Compact, railed
Streamlight TLR-1 HL	3.39 in (8.61 cm)	4.32 oz (122.5 g)	Full-size pistol
SureFire M640DF	5.56 in (14.1 cm)	5.5 oz (156 g)	Long gun
Streamlight TL-Racker	8.00 in (20.3 cm)	12.1 oz (343 g)	Shotgun forend

Roughly eleven to one, end to end — and the ProTac 2.0 Rail Mount HP is heavier still at 9.06 oz (257 g). Holsters count too: SureFire notes the XC3's slim profile suits many existing holsters.

Output: the short version

Lumens measure total light; candela measure how hard it is concentrated into the centre of the beam, and candela — not lumens — governs useful reach. Two lights can share a headline lumen figure and behave completely differently.

One family proves it: the ProTac 2.0 Rail Mount gives 2000 lumens at 17,700 candela and 266 metres, the HP version the same 2000 lumens at 85,000 candela and 583 metres. Read lumens vs candela explained rather than choosing on the box figure.

Power: CR123A primaries or a rechargeable pack

A genuine trade, not a right answer. CR123A cells sit in a drawer for years and need no charging discipline — the TLR-1 HP runs 1000 lumens at 65,000 candela to 510 metres for 1.75 hours on two. Rechargeable packs cost nothing to run and usually deliver higher peak output, but they need a routine and are flat when you forget.

Here is the part most listings gloss over: on a multi-fuel light the headline number is the rechargeable figure. Fit a primary cell and it gets dimmer.

Light	Rechargeable pack	CR123A primaries
Streamlight TLR-7 X USB	725 lm / 9,500 cd / 195 m, 1 h	550 lm / 7,200 cd / 170 m, 1.5 h
Streamlight TLR-1 HL-X USB	1500 lm / 20,000 cd / 283 m, 1 h	1000 lm / 15,000 cd / 245 m, 1.5 h
SureFire M640DF	1500 lm / 16,000 cd / 250 m, 1.5 h	1200 lm / 12,800 cd / 220 m, 1.25 h
SureFire M640DFT	700 lm / 100,000 cd / 632 m, 2.75 h	600 lm / 90,000 cd / 600 m, 1.75 h

Note that the primary column is usually the longer runtime, so a rechargeable light is not automatically the one that lasts. A light named for its rechargeable figure is being sold at its best case: the ProTac Rail Mount 1L-X USB Pro is named for 850 lumens on its SL-B9 pack and gives 500 on a CR123A. Others are pack-only in practice — the ProTac 2.0 Rail Mount HP runs a 4,900 mAh SL-B50, Holosun's P.ID an 18350 — and Holosun publishes no runtime for the P.ID, P.ID-K or RAID, so those cannot be compared on paper. See the rechargeable weapon lights.

Activation: how you turn it on

• Tailcap — the default on long-gun rail lights. SureFire's Z68 presses for momentary-on and presses further for constant-on, with a raised guard and lock-out
• Paddles and toggles — the pistol answer, worked with the support-hand thumb. The TLR-7 X USB uses ambidextrous rear paddles, high and low interchangeable; the TLR-9 supplies both to match the trigger guard
• Pressure switches in the kit — Streamlight bundles rather than sells separately. The TLR RM 1 System includes a remote pressure switch where the Light Only version does not, at the same 500 lumens and 11,000 candela
• Remote tape switches bought separately — the SureFire approach, and the one that catches people out

A Scout Light body plus a remote switch is a system, not one part. A Scout leaves the factory with a click tailcap; to run a tape switch you first fit a tailcap with a socket, then plug a switch into it. The DS00 switch assembly is a click on/off pushbutton whose receptacle accepts the ST07, SR07 and SR07-D-IT remotes, sold separately, both switches working independently. The UE rear cap deletes the pushbutton — socket and lock-out only. The UEE Dual Fuel cap suits high-output Dual Fuel Scouts such as the M600DF and M640DF, and is not necessary on a Turbo Scout Light Pro.

Then the pad. The ST07 is momentary-only, 7 in cable, adhesive-backed Velcro. The SR07 adds a constant-on pushbutton beside the momentary pad on a snap-on Picatinny clamp; the dual-lead SR07-D-IT drives a light and a laser aiming device, separately or together. The DS07 and DS-SR07 sell cap and remote as one purchase. To put the pad under your hand, the CSM-07 and CSM-09 clamp to M-LOK on 7 in and 9 in cables, the CSP-07 and CSP-09 the same on Picatinny. All need a light with a plug socket — on an X300 or X400 that means an XT tailcap — and the Micro Scout Light Pro is excluded. See weapon light accessories.

A remote usually costs sealing: the ProTac Rail Mount 1 is IPX7 with the push-button fitted and IPX4 with the remote.

Laser or no laser

A combined unit saves rail space and one set of controls, and costs weight, a second thing to zero and often a lower water rating. The light-only TLR-9 is IPX7; the TLR-10 G — same 1000 lumens, 10,000 candela and 200 metres, green laser added — is IPX4, as is the TLR-2 HL G, whose fuel budget splits three ways: 1.5 hours on light alone, 1.25 hours on both, 17 hours on laser only.

Streamlight's green units are 510–530 nm Class 3R below 5 mW, the red on the TLR-6 640–660 nm. On a very small pistol the laser may be the practical aiming aid: the TLR-6 HL G for the Glock 43X/48 is 1.12 oz complete, gives 300 lumens and a green laser, and ships with three SL-B2 cells and a two-bay USB-C charge case. See weapon light laser combos.

Infrared models are a different thing, and frequently misread. An IR channel is an illuminator for night vision — it emits nothing a naked eye can see, and it is not a visible aiming laser. The ProTac Rail Mount VIR Pro pairs white light at 1100, 540 and 120 lumens with 940 nm infrared at 2,300 mW high and 600 mW low. The TLR-VIR II gives 300 lumens of white and, on infrared, an 850 nm illuminator of at least 600 mW/sr plus a Class 1 infrared aiming laser below 0.8 mW. Holosun's P.ID Dual carries both kinds: a visible green 520 nm Class 3R laser below 5 mW and a separate 830 nm Class 2M infrared laser below 0.7 mW. Without night vision, the infrared half of any of these is dead weight.

What this range does not cover

This is a weapon light range, not a torch range — the only handheld is the ProTac 2.0 at 2000, 570 and 100 lumens, so a general-purpose pocket torch must be sourced elsewhere. There are no standalone aiming lasers: a laser comes built into a combo light or not at all. Every separately sold switch part here is a SureFire Scout component, so a Streamlight remote arrives inside a System or kit part number, and the XT tailcap an X300 or X400 needs is not stocked.

Short version: if you run X, look at Y

• Full-size railed pistol, one light for everything — TLR-1 HL or X300U-A, both 1000 lumens on two CR123A
• Full-size pistol, reach over spill — TLR-1 HP at 65,000 candela, or the X300T-A Turbo at 66,000
• Compact or subcompact railed pistol — the TLR-7 X sub cut for your frame, or the XC3 Sub
• Glock 42 or 43, no rail — TLR-6, 1.12 oz
• Carbine on M-LOK, weight-conscious — M340C at 3.65 oz, or the TLR RM 1 HL-X USB System at 3.12 oz
• Carbine, distance the problem — M640DFT at 100,000 candela, ProTac 2.0 Rail Mount HP at 85,000, RAID at 80,000
• Mossberg 500/590, 590 Shockwave or Remington 870 — the matching TL-Racker forend
• Night vision — TLR-VIR II or ProTac Rail Mount VIR Pro

Shop the range: all weapon lights, the rechargeable models, laser combos and switches and accessories, or by brand with SureFire and Streamlight. Settled on Streamlight? The TLR comparison guide takes fitment model by model. £5 tracked UK delivery in 7–10 business days.