SureFire makes some of our favorite rifle lights, but with so many options, it can get confusing. Below is a basic spec chart of all the SureFire rifle lights we offer or recommend, all in one place for easy cross reference.
| M340C | M340DFT (Turbo) | M340V | M640U | M640 DF | M640DFT (Turbo) | M640V | |
| Output (Lumens) | 500 | 18350: 650 CR123: 350 | WL: 250 IR: 100 mW | 1000 | 18650: 1,500 CR123: 1,200 | 18650: 700 CR123: 600 | WL: 350 IR: 120 mW |
| Peak Beam Intensity (Candela) | 7,600 | 18350:95K CR123: 55K | 9,300 | 11,300 | 18650: 16K CR123: 12,800 | 18650:100K CR123: 90K | 12,750 |
| Runtime (Hours) | 1 | 18350: 0.75 CR123: 1 | WL: 1.5 IR: 6 | 1.25 | 18650: 1.5 CR123: 1.25 | 18650: 2.75 CR123: 1.75 | WL: 2.5 IR: 16.75 |
| Distance | 175 m | 18350: 616 m CR123: 459 m | 190 m | 213 m | 18650: 250 m CR123: 220 m | 18650: 632 m CR123: 600 m | 225 m |
| Weight (With Batteries) | 3.65 oz (103.5 g) | 5.11 oz (144.9 g) | 3.4 oz (96.4 g) | 4.8 oz. (136 g) | 5.5 oz (156 g) | 5.5 oz (156 g) | 4.15 oz (117.7 g) |
| Length | 4.1 in. | 4.8 in. | 4.1 in. | 5.5 in. | 5.56 in. | 5.9 in. | 5.5 in. |
| Length After Mount | 2.1 in. | 2.77 in. | 2.05 in. | 3.42 in. | 3.43 in. | 3.89 in. | 3.37 in. |
| Bezel Diameter | 1.125 in. | 1.258 in. | 1.06 in. | 1.125 in. | 1.125 in. | 1.258 in. | 1.06 in. |
| Dual Fuel? | NO | YES | NO | NO | YES | YES | NO |
Lumens vs. Candela
Both lumens and candela are necessary measurements to consider, but they don’t line up perfectly. A high candela light won’t usually have a high lumen figure and vice versa. So, what’s the difference? Put simply, lumens are the measure of total emitted light, and candela is the measure of light intensity. High-lumen lights will have a ton of spill or flood, but they may be lacking in the beam intensity department. The reverse of that generally applies to high-candela lights.
A perfect example is the M640DF and the M640DF-Turbo. The M640DF prioritizes high-lumens, while the M640DF-Turbo prioritizes candela. The 640DF is extremely bright and has tons of flood, but the light doesn’t throw as far, and it’s not good for punching through fog or photonic barriers. The M640DF-Turbo has less flood, but its high candela allows the light to throw farther and push through fog and photonic barriers much easier than the standard DF.
Compact vs. Fullsize and Battery Commonality
When choosing a SureFire weapon light, a major decision is whether you want the Compact M340 series or the full-size M640 series. They both have pros and cons, so understanding both options and how they apply to you is important. The M340 series offers a compact light package that is relatively lightweight. However, runtime and overall output are generally lower. The M640 is the opposite; You get more runtime and output at the cost of weight and overall size. Another factor to consider is battery commonality. If you have other devices that run on 18350s, you may not want a weapon light that takes 18650s and vice versa. This is where the Dual Fuel lights from SureFire really shine, no pun intended. These lights can run off of 18350 or 18650 batteries and the more common CR123s found in most IR lasers and some optics, adding an extra layer of redundancy and overall convenience.
